It is really hard to have a cool side and a warm side with a 10 gal. I would think that a 15 gal would be tha smallest. That is what I have for my new born. It is not too big and not too small. The hot side is 90-92 and the cool side is 80-84. With humidity at 50-60%. I have to spray to but I also use towels on top of the tank. I would not worry if she doesn't eat because that is what bp do, a lot. Now when they regurgitat it then worry. I would just take it to a vet. Just get a bigger tank and make sure the temp, humidity, and housing is all correct.