I think I broke my foot. Do I go to orthopedic doc or er?

Either. You need to be seen asap to have your foot examined. So go whereever you can be seen 1st.
It depends. If you have an open wound, can't walk, have uncontrollable pain, or have a deformity of the foot then you should go to the er. They will typically stabilize the injury, get your pain under control, and treat the wound as needed. Then they will likely refer you to an orthopedic physician. If your pain and symptoms are under control and no wound or deformity exists, go straight to an orthopedist.