Open Question: head injury, concussion?, hit my head,?

I hit my head on my way out of the subway train, on the gates rim. This was exactly 3 weeks ago. First, it was just a normal hit on the head, it didn't feel unusual. But I became more and more frightened as the numbness on my head (constant), and a short, reasonably sharp headache (occasional) persisted. I hit my head on the top right roof of the skull, and the numbness is on my bottom back