I have a problem with my ankle cause of an old injury and now if fells like its popping?

So last spring I sprained my ankle and then it got better but when I started basketball season it started to hurt again. The pain moves around but its mostly on the front outside. I noticed today though that it feels different from my other ankle when I walk and it either feels kinda like its popping/cracking or it needs to pop/crack. I'm doing rehab at school but so far it hasn't helped (but i haven't been able to do lots due to games and no school). Do you have any idea what could be wrong?