I got a migraine shortly after this incident last night, so it's hard for me to really know whether my symptoms are from a concussion or just from the migraine (since they can both have very similar symptoms). I was sitting down on a concrete step and I wasn't looking through my glasses, so I misjudged the height of the step, thinking it was a couple inches or so higher than it was, and so I sat down pretty hard and it made my head feel weird. Could this be enough force to cause a concussion?