I know how you feel as I went through that as well. As I said I was taking him to the vet everyday for his IV fluids and injections (antibiotics, anti nausea, cortisone)the vet was trying everything. Twice during that month he had started to eat a bit and drank water on his own, even scratched his pole and jumped onto bed with me and stuff but after two days he was back to not eating and drinking. The ultrasound showed no tumor but I don't know if there was a tumor somewhere other than his belly. It is a terrible situation. You see some improvement and you get your hopes up and I thought it was a miracle which only lasted two days or three. Keep on trying. Take him back to the vet. He may eventually get better, you can never be sure. God I hope and wish he gets better. Lots of hugs to you both.