We recently had to put to sleep a kitten we had rescued from the shelter who had a URI. Now my resident cat has one as well and had injectable antibiotics Thursday. Today he woke up stuffier than before and he won't eat or drink (we are syringe feeding him). He's 8 and otherwise healthy. I am panicking that he won't pull through even though I've read URI's are generally only a nuisance. Please tell me what more I can do (I have a humidifier going in the room where he is) and he's receiving additional antibiotics as of today (doxycycline). I'm terrified he won't recover.