Cat with cold won't eat

My cat, who has a very bad upper respiratory infection, won't eat anything. I've gotten her to drink a little bit of tuna juice, but that's it. She didn't drink water for 8 days (we had to start giving her an iv every day), and just recently started drinking again. She does seem to be doing better, and isn't dehydrated. What would you suggest doing for her? We don't know exactly how old she is, but we think 6-7 years old. She is getting very skinny and I'm worried about her. The vet said to just force feed her, but she hates that and we can only give her so much at a time.