I'm concerned about my bird's health

[Lolathelovebird]

I got my lovebird exactly two weeks ago from a pet store. She is a year old (at least that's what the pet store employee told me). I'm very concerned for her because I believe that she had been fed a millet only diet for her whole life. She refuses to eat anything but millet, boiled eggs, and pears, and from what I've read, these three foods should be fed only as treats. I've tried feeding her lentils, brown basmati rice, carrots, cucumbers, bell peppers, parsley, mint, watercress, cauliflower, peas, green beans, walnuts, almonds, cashews and sesame seeds, but she refuses to eat any of it. She is also drinking a lot of water which makes me scared that she has diabetes or something of that sort. She looks tired all the time, and at the moment while she is having out of cage time she is just sitting very still, which doesn't seem normal. Her poop is very liquidy.She also always bites her left foot, and I fear that she has an infection. I also fear that she's stressed out or something, and that's why she's standing very still. She eats from my hand and flies over to me and perches on my finger when she's out of her cage, which makes me believe that she trusts me, or at least somewhat. When I put my hand in her cage though, she moves far away from it, so is she scared of me?? Also I forgot to mention that when I got her from the pet store, the pet store employee grabbed her in such a cruel way to get her into the new cage I bought for her. The cage she was in was so small. Poor thing was so scared of hands for like a week since we had gotten her, and would go crazy when I had to put my hand in her cage to clean it. She ate from my hand on the the tenth day, and after that I started target training and she caught on pretty quickly. She also learned the 'fly to my hand' trick in probably less than ten minutes, which I did not expect at all. I am writing this as she is now out of her cage, and she's just sitting on top of it very still. She has been like that for the last 30 minutes. She doesn't play with her toys at all (made out of 100% natural jute rope and paper and popsicle sticks). And last thing I want to say is, I suspect that the new cage I bought her (65cm width×48cm hight × 40cm length, from another pet store) is galvanized or coated with zinc or something. Also one day after I bought the cage, two bars broke of and I had my sister patch it up with jute rope. I reaaaaaaLly want to take her to the vet for a checkup, but my parents think that I'm just being too panicky and over obsessing over tiny little things. Am I really just too panicky as they said???