Ok, hope this is helpful. You should try to feed her some Science Diet Critical Care(and no, I don't like SD) but this food is what they feed in pet hospitals with critical patients and it will spark their appetite sometimes. Also try giving some human grade tuna and juice or clam juice. I have been where you are numerous times. Sometimes my kitties have come back(I had a 21 year old, a 17 year old and numerous others that didn't live to be over 14) from not eating. I have also tried the stinkiest canned cat food that I can locate and they will sometimes eat that. When they don't eat any of that, then I don't know what else to suggest. Make sure that you try everything but don't wait until your kitty is so emancipated that she is in pain. It really is very hard to tell with cats because they tend to hide their illnesses until they are sometimes very sick. I am in no way an expert and am not a vet, just wanted to give you some suggestions.
Wolfgang Von Ironwood, GSD