Ok i have been lifting like crazy here latley and i dont feel like i am getting weak i feel like i am getting stronger but what is wrong i just measured my bicep and it use to be 15 inches and its 14 1/2 now.
maybe you're lifting to much and not giving urself enough time to heal? it could be a entire spectrum of things.. ur weekly workout sched, what u eat in a day, how much u sleep, etc
***EDIT*** and remember u need ~10lb of muscle for ~1" on ur arm