I am having trouble getting my cat to eat after huge spider bite ordeal!?

[StunDem]

my cat got bit by a brown recluse and is now in recovery after a surgery to remove an absess. she was doing great. she recovered very quickly from the bite and the surgery. she was eating and drinking normally. the fever left and she was becoming more active. she now is getting pretty bad again. it has been almost a month since she was bitten. she now eats hardly at all. and the weirdest part.. she tries to eat the clay cat litter? i am completely puzzled and would like answers. i would return to the vet but am already 1500 deep with this kitty. help anyone? i dont mind force feeding her...i force fed her meds for the past month but really want to know what else if anything could help make her better. really dont want to lose her