What Causes Swelling And Bruise In Thumb?

I fell sledding two weeks ago. I fell directly on my thumb. I heard a big crack when I landed on it. it was swollen around the knuckle at the base of my thumb and bruised. It is not as swollen or bruised anymore but it still hurts deep in the base and I have no strength. Also, the knuckle at the base of the thumb is sticking out like a big lump.