Leos are very hardy and can make comebacks like you don't believe, but it takes work on your part. Let me repeat what I just said: YOU HAVE TO HELP OUT. So far, it looks like you haven't done squat and apparently haven't done squat for a long time. It takes a while for a leo to degenerate to the point where you can see its backbone. You'll only have more work ahead of you now, since her earlier health signs didn't clue you in as they were declining.
First things first. Get the temperature right. This is the most basic of leopard gecko care and shouldn't be overlooked. If it's burning your hand, how do you expect your gecko to lie her whole body down on it? At least put in more hides so she can choose which part of the heat gradient is the most comfortable for her.
Secondly, find a reptile vet. If you don't want to pay for a visit, then maybe you should reconsider being a pet owner. Coming onto this forum isn't going to solve all your problems. You have to find out why she got sick then shell out the dough to fix it. Hey, I'm a poor college student, too. In fact, I don't think any of us here are rich. (If you are, please speak up and I would like to be friends with you.
) However, I do not cut corners when it comes to my leos, especially when they need medical attention.
If she has been throwing up a lot, don't expect her to be able to handle eating crickets. Her stomach is in no condition to digest regular food right now. You're gonna have to start a regimen that includes putting bugs into a blender to make a slurry. Follow this link for more instructions.
I guess I should conclude with an apology for blowing up. But I won't, because I have little sympathy for irresponsible pet owners.
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chickabowwow

3.2.2 leopard geckos (Rosie, Locke, Lisa, Caesar, Tommy)
and 1 more egg a' cookin' 