Jeeper,
I know what you're going through.....just 4 months ago I had to put my Dobermann down. She had the canine form of hepatitis, and was in liver failure. She was on so much medication & special diet for her liver, but everytime her blood tests came back from the lab she had gotten worse. I think it was something like 3 weeks from the time she was diagnosed to the day we made "the decision". She went downhill so fast, it was unbelieveable. Watching it was really hard! The night before we did it she was up all night, vomitting, diarrhea, restless, she hadn't been eating much of anything in days. She was only 6 yrs old.