You say you've had her for only a month and have taken her to the vet "many times"? Well it could be a stress thing if she keeps getting dragged out and poked about by a vet just after arriving at her new home.
My BP didn't eat for the first week I had her but I left her completely alone apart from changing her water.
Just noticed - the temps are a little low for the warm end - try bumping up warm end to 92-94.