What's wrong with my leg? 10 points.?

I was sled riding today. I had a sled tied to the back of a four wheeler and my friend and I was riding the sled. We hit a bump and we both flew off the sled and she landed on my leg, which was kind of turned back behind me. My leg hurt really bad at first and I couldn't stand up. Then I stood up but it kind of hurt to walk on it. Now it doesn't really hurt when I stand straight up, but it hurts when I bend down on my leg. The pain is in my lower leg and it's kind of bruised and hurts when I touch it. I just noticed that I have a small bump where the bone is. Does anyone know what could be wrong? I don't think it would be broken for the simple fact that I can stand on it. Could it possibly be a hairline fracture?