to get a second opinion. I am surprised he did not worm her though, with a fever, he might not have wanted to do this. I know this sounds bad, but if you can make an appt to see another vet, and save some of the sick in a plastic bag, they will be able to determine what is wrong with kitty easier. Also did they even culture her stool? I would go to the store and get a small bottle of pedialyte and some chicken flavored baby food, and mix it up into a watery gruel and see if kitty will take it. Are her gums pale pink or happy pink? Does she have fleas, she could be anemic? There are many things that could be wrong with her, I would get a second opinion.