my cat is 17 years old, in the last year he lost weight, 3 month ago he had extensive blood test and everything came back very good, Also in the last year he became choosy about his food, since, once every 2-3 week he has a day that he will not eat, sleep a lot but than things get back to normal. 3 days ago, he vomited (but that happens) in his room, when I cleaned it, he went out only to return the next morning. I forced him inside, but in the afternoon he asked to go out agin, diapering till the next morning again, not wanting to eat much, rather, he drinks a lot. Sometimes he cries too. Any Idea?