Did i break my foot? or how could i break it?

First off don't call me stupid or anything, please just answer my question. I wanted a cast cause my foot never healed right after I sprain. So I hit the middle of my foot with a sledgehammer. Now it hurts to move my big toe or put any pressure on it. It's red and a little swollen and it hurts. Is it broken and should I go to the er or if not how could I break it!