For the past 3 days, my moms kitty has been acting funny, last night he was able to walk, but this evening came to realize he can barely walk using his hind legs...i have no clue as to what this can be, he isn't eating right, hes not using the litter box like normal, thought it might Cystitis, but when i was reading up on it, it said nothing about affecting how a cat walks. im really scared, and right now we dont really have the money to take him to the vet. 