My heart goes out to you. I lost my sweet cat named Spot to the same thing a few years ago. My vet thought she might have eaten some of the contaminated food that was out back then. Spot would eat cooked chicken livers, not much else. This may be hard to hear, but please try to recognize when the IV fluids are not helping your sweetie to feel better and have the courage to do the right thing. I will be remembering you in prayers, I know how heartbreaking this is.