We took Scooter to the vet yesterday after having cold/URI symptoms for about a week that just weren't going away. He was very lethargic and sleeping lots in secluded areas by himself (in the closet, under the beds, or behind the couch). He wasn't too interested in eating and, when he would eat, it was only a little wet food and he wouldn't touch the dry stuff. He had actually lost a bit of weight. He weighed 9 pounds at the vet, but we could feel the bones in his spine and hips more than we ever could before. He has always been a very lean cat. The vet was almost 100% certain that it was some sort of viral infection that he got from our new cat, Abby, that we adopted from the shelter a few weeks ago. For some reason, our other cat, Bailey, never got it, just Scooter. The vet put him on clavamox to take once every 12 hours. He has only had 2 doses so far, but what an improvement! He ate almost an entire can of wet food before bed last night and, just now, he actually passed up his wet food to eat some dry food (poor guy was probably finally sick of eating nothing but the wet stuff for a week straight), and he even licked almost all of the peanut butter off my toast! He still has some sniffles and sneezes, but he is eating so much more and last night he actually slept in the hallway outside of our bedroom instead of hiding somewhere. He's also much more awake now and is actually out and about in the house. He has discovered the Christmas tree.
I'm sure that he'll get even better after a couple more doses of the clavamox and get 100% back to his old self. He's due for his next dose in about an hour. I'm very happy with the progress so far!