Not sure what is wrong...advice?

My 'sleepy' chin may have taken a turn for the worst. What I thought was him finally warming up to me may have been his way of saying "I'm not well". He is still eating, but slowly (I gave him critical care along with orchard grass and a raisin and instead of inhaling it, him nibbled.) And he is still drinking (fresh water). Also has normal poo. Problem is that he is more so lethargic and stays at the bottom of his cage. When I hold him, he nuzzles up close to my lap or under my neck, shifting occasionally, but stays until I move him. He gets small bursts of energy where he hops a little but has trouble making jumps to low platforms 50% of the time. He even tried to hop off of my shoulder today before I stopped him and he nuzzle back up. I am worried that he perhaps sprained his leg some how, as he is not consinstant in any symptoms of illness or major injury, and is taking his own time to recover. I say sprain because I touched from hip to foot and he didn't pull away or make any noise. I also know that to be 90% sure of anything I would need him seen by a vet, unfortunately I can not afford to take him until next paycheck (unless someone knows of a bill me later vet near cleveland?) Not trying to complain about my situation. I want to help him as best I can with what I am able.