Pain on the outer side of knee..what is it?

I was playing volleyball and I collided with another player in the air. I landed weird on my left leg. It didn't hurt too bad when it happened, but then it got steadily worse. It's on the outer side and it hurts to bend it too far and to push off of my toes, I can also not pivot on it. And if you are familiar with the term- Anterior draw test, that hurts.. A lot! It just achy as I sit here typing this. But when I move it wrong it is a very sharp pain! Any idea what I could have done to it? Please help!