A concussion is when you fall unconscious and go so brain dead that you can't even tell how much time has passed by since you've had it right?

I've had that happen to me before. I went sliding down stair rails one time, I was about to run into some people so I tried to stop but ended up falling off the rail and landing on my head. As soon as my head hit the stairs I found myself somehow "warped" (don't laugh at this, it's the best word I can think of to describe this) to the ground. My friends claimed that I was lying down on the ground unreactive for a minute. The strange thing was that I literally just hit my head on the stairs then ended up on the ground getting up after realizing I was down on the ground without experiencing the rest of the tumble down the stairs or the minute where I stayed unresponsive.