He seems to have no real strength, barely walks to his bowl to eat the rest of the time he's sleeping. When he eats its not much, it seems to tire him out chewing so Ive given him some milk and soft food so he doesn't lose any more weight. He has rings around his eyes like a cold. He won't go out the window to use the potty he goes on my bathroom floor. He smacks his chops like his throat is dry or something in there is bothering him.

And of course you have taken him to the vet...

It's past time to get him to the vet.
This could be caused by any number of things.