What's wrong with my knee?

I was playing basketball saturday and sunday and all was fine. Just until yesterday when I got back home, the backside of my right knee started feeling pretty weird. It feels pretty weak now. It feels as if it was dislocated and popped back in. The thing is though, I still have full range of motion, its not swollen, it doesnt hurt. The only thing I notice is that something pops in the back of my knee when I do certain groin or hamstring stretches.. Help please?