heh, I've done it, too. In my case it was in the '70s and I stood up to crack my head against the corner of an overhanging cabinet. Ouch. I think I was more successful than you, tho, re: a concussion. I never went to a doctor so I don't know for sure, but for a day, I felt slightly nauseated. Along with the horrid headache, of course.

Many lessons are learned the hard way, unfortunately. Hope you're back to normal soon. :)