What exactlly did you do? Did you twist ur knee, get hit from the side? I have gone thru my fair share of knee problems. I am actually wating on a surgery date myself.
I say ice it, keep it elevated. If it doesnt get better in a few days give a orthopedic surgeon a call.
I second Dr. Joseph Buran. He is one of he most well respected orthopedic surgeons in the area. He was a professor at the UB medical school, and he is/was the orthopedic surgeon for the Sabres and the Bills. I have full faith in him.