I'm going to second the addition of CBD Oil to the Melatonin, because it works absolute wonders for anxiety caused by pretty much everything and anything, it also influences not only sleep, but restful REM sleep, which is very important, and it is 100% safe in-combination with pretty much any prescription medications, even MAO Inhibitors (which you can't take ANYTHING ELSE if you're on them)...
Half the battle is actually determining the cause of your anxiety, and you've already done that, it's Skittles not being with you/around you when he's asleep...And I wouldn't be thinking that this is an "irrational" anxiety, as it's completely understandable why this is happening to you when you put Skittles to bed...I am single, I live alone and have for about 6 years now, and though I love living alone and being single, my birds and my dog are my family, and since 2012, when I was diagnosed first with stage-3 Endometriosis, had a total, open-abdominal Hysterectomy and Bi-Lateral Salpingo Oopherectomy (they took EVERYTHING, I have no organs left, lol), and then was diagnosed with very early Vaginal Cancer (really Cervical Cancer, but since they took my Cervix they call it Vaginal Cancer, even though it's Cervical-cells that were left-behind that turned malignant; yes, I'm such a gifted, talented person that I can get Cancer of an organ that was removed 2-years prior to the diagnosis...Beat that!)...So at some point I decided to stop breeding and hand-raising parrots as I had been for just about 20-years, I re-homed most of my breeders to an Avian Refuge for captive-bred Parrots/Birds, and a few that were actually pretty hand-tame I re-homed at the Avian Rescue I work for...And that was when I made the decision to again add a parrot to my family and life, and I found Bowie as a little 13 week-old baby in Petco by pure chance...And since then I have scaled-back working and have been trying to actually enjoy life instead of working 70 hours a week to make a bunch of money I have no time to spend or enjoy anyway...
The part of my story that relates most to your story is that I'm an Opioid Addict, which started back around 2008-2009 when the Endometriosis and the Ovarian Cysts it started causing, along with my lovely chronic Kidney Stones that I've had since I was 19 in college, caused me to start receiving tons of legal prescriptions for narcotic opioid pain-killers...And you know the rest of the story, as my opioid addiction progressed the exact same way that everyone else's does; no one uses opioids to party with, though a lot of people just assume that when they see a heroin addict that "it's their fault" and "they did it to themselves", when this couldn't be further from the truth...And I also work in the Car Business, I have since 2003, and it's second to only Rock Stars and people who work in the Restaurant Business for it's rampant and totally-accepted, constant drug use and abuse (combination of working lots of hours every week, being with your colleagues all the time, making a ton of money quickly, and needing something to make this life tolerable)...So when I went through the 3 different major surgeries in 2012-2013, then the treatments, medications, etc., I wasn't dealing with my addiction at all, it was just my life. I finally decided that I didn't want to end-up dead or in prison, so I got myself into a Methadone program in 2016 that includes both one-on-one therapy and group-therapy, and things are finally good...As far as meds I take daily, I take the Methadone once daily, I take a daily Hormone-Replacement (Premarin) because I have no Ovaries and thus no Hormones at all (I went through surgical-menopause at the age of 32), and I also unfortunately have to take a prescription stimulant (Phentermine) to counteract the Methadone and the lack of Hormones, because without one I'm just a complete Zombie...That's it, I don't take any type of anxiety meds, no SSRI's or anti-psychotics, I've never suffered from OCD or Depression, however I do suffer from severe PTSD as a result of my childhood (that's another story)...I've managed to stay off of any psych or anti-anxiety drugs, but I was considering it, but most of them do not mix with Methadone, especially Benzos like Ativan, Xanex, Valium, Vistaril, etc.
***So my Methadone Counselor suggested CBD Oil, as it does not interact with any prescription drugs at all (there is a lot of information about CBD Oil online, and all of your questions can be answered, along with talking to your doctor about it as well)...I highly suggest that you look into it, because it has worked wonders for me in-regard to my PTSD symptoms and my inability to sleep...And PTSD symptoms are similar to Anxiety, or rather PTSD basically causes eventual anxiety if you let it...Now let me preface this with I HATE WEED!!! AND I ALWAYS HAVE!!! I have no idea why, I obviously have nothing against using Weed, I think it's much, much safer and much less harmful to your body than alcohol is by-far, and I could care less what other people do...I'm obviously not judgemental about people who use drugs, lol, as I've spend most of my adult life using them/abusing them myself. But for whatever reason I just have not EVER liked Marijuana. Period. Not in High-School, not in College, and not since. I just get tired, space-out, and fall asleep. I know many people who smoke all day long while they're at work for 12-hours a day, talking to people and dealing with the public, closing sales, etc. while they're high, and I can't even imagine how they do it...Just not my jam. So when the subject of me trying CBD Oil to control/subdue my PTSD symptoms, which tend to come-on when I'm alone and have time to think about things, or when I'm at home alone and a "Trigger" pops-up, which it does every single day since my "Triggers" are people in my family, namely both my parents. And then I get myself worked-up, and have to calm myself down...At first with the birds they were enough, and often they still are. But just like you, my birds are not always around, even less than Skittles is with you because I'm not home all day long with them. I play Guitar, alto Sax, and Drums, among other instruments, so they sometimes help, but again, I don't always have them with me...I have been a hard-core Mountain-Biker since the age of around 10, and it really helps tremendously to just jump on my Bike and go, but again, can't always do it. Exercise, by the way, even if you don't enjoy exercise, does work wonders to stop Anxiety, Panic Attacks, PTSD Attacks/Episodes, even Depressive Episodes...As far as Exercise goes, the key is finding WHAT ACTIVITY YOU LIKE TO DO, and then doing it whenever you feel the Anxiety first coming-on. And there are THOUSANDS OF PHYSICAL ACTIVITIES that you can try if you don't know what type of Exercise you like to do. For some people it's just going for a 15-20 minute walk around their neighborhood, or going for a Hike in the woods or on a foot-trail that is beside a stream or river that is audibly relaxing. Jogging, Running, Biking/Cycling, Skateboarding, the list is endless...I actually use my Nintendo Wii in the winter and I can't Mountain Bike, and I spend an hour doing Wii Fitness on the Balance-Board. And Video Games, while not really "exercise", are honestly a very good outlet for stress and anxiety,, especially games like Grand Theft Auto, Call of Duty, Need For Speed, etc. But still you can't always do whatever activity/exercise it is that works for you when you are feeling anxiety, BUT YOU CAN PULL OUT YOUR BOTTLE OF CBD OIL AT PRETTY MUCH ANY TIME. And since yours is coming at nighttime, after you put Skittles to bed and before you yourself go to sleep, then it's the perfect time to try using CBD Oil, and if it works for you then you have found an Anti-Anxiety aide that you can literally use AT ANY TIME BOTH SAFELY AND LEGALLY...
I would talk to your doctor about you at the very least trying CBD Oil, As well as you doing your own online-research about it, because there is still a good percentage of doctors, therapists, counselors, etc. who know nothing about CBD Oil at all, and many of them like myself related it to Weed, and immediately dismiss it as either a safe or a valid, effective remedy...So you have to advocate for yourself sometimes, and bring your own research with you to your doctor's/therapist's office. Seriously, it's nothing at all like using Weed, if it was I wouldn't use it, even if it did help me (as I'm sure using Weed would help me, that I know, but I just can't stand using it, lol)...CBD Oil doesn't cause any type of "high", nor any type of hallucinations or "spacing out" like Psychedelics and Weed do. If I had to describe the way that CBD Oil works to eliminate Anxiety/PTSD Episodes, I'd say that it works very much the same way that Benzo's like Valium, Ativan, and Xanex work to stop the Anxiety, but with absolutely NO drowsiness, no confusion, no fatigue, or any of the other side-effects that Benzo's produce...If anyone has ever tried using Kratom for their Anxiety, CBD Oil works in a very similar way (Kratom is getting a bad-rep right now, I don't know why because it's not a drug/plant that produces any type of "high" or euphoria at all, it's very similar to CBD Oil, but what people don't know about they fear I guess, just like anything else...)...