I'll just quickly add that if you actually have a concussion, chances are you will be quite happy to just lie around and do nothing, at least for the first week or so. It can be a quite serious condition, and lets you know. I vividly remember my dh getting a concussion and being ordered on a weeks bedrest, no reading, no tv. I thought he'd go insane, but when I got home he was quietly lying on the sofa and had been there all day, happily doing nothing at all while time flew. I had the same experience a few weeks ago.