I would find a another vet. Not going for 3 days is not normal. I would tell a new vet about the not peeing for 3 days, not pooping for 2 and the not moving. Yes cats sleep allot but they normally sleep and play in bursts. This almost sounds like diabetes. When our Patches got lethargic we had her checked, she had become diabetic. A insulin shot a day and she was fine for 16 years.