That sucks.. We had a similar situation but the vet really helped us out.
My brother's bearded dragon (small desert lizard) wasn't eating and could barely move. My dad took him into the vet and the vet kept him for 4 days. He called us every day - sometimes twice - to report on the status of his lizard. The vet gave us instructions for how to force-feed the lizard with a syringe and mash up his food and everything. He also had us get a hotter heat lamp. After we came by and picked up the lizard, the vet came a few days later just to check on the lizard. The lizard was a very slow recovery, though, and the vet said he had only a small chance of recovering.
Well, my bro and I took turns force-feeding the lizard (a really annoying process cause you can't help but feel bad for the poor lizard) for 2 whole months. However, towards the end of that two months, the lizard started moving more and eating voluntarily (after we held food in front of its mouth). Now, the lizard runs around like any other active bearded dragon and he catches crickets.
My family was starting to feel pretty jealous of the medical treatment my brother's lizard got.

Perhaps your kitten can have some luck like that too.