Could be any of a number of things...

Could have broken one of the LCA (Lower Control Arm) or trailing arm bolts, could have bent the LCA itself, could have bent the trailing arm, could have messed with the shock/suspension mount...take your time and take some clear pics of the area and post em up...if you need somewhere to host the pics, let us know and someone will hook you up.

Glad to know you weren't hurt (I'm assuming) and welcome to the forums