Any ideas what I did to my arm?

Yesterday morning I banged my forearm into a metal bed frame pretty hard. I didn't think too much of it at first, I was busy and it didn't hurt that bad although it was swollen and slightly bruised. Then in the afternoon it started to hurt pretty badly and went slightly numb. I iced it last night and its basically feels the same today as yesterday afternoon, although its slightly more painful but less numb. I feel like it can't be broken because I can still make a fist, bear weight on it, and rotate it with some pain. I do have some trouble moving my hand down, but I can still do it. I've broken bones in the past, although not my arm, and I was generally unable to move the injured limb or if I could move it it was only with a lot of pain. So maybe I just bruised it badly, I'm not sure.