Similar thing happened to me. I crashed in a motorcycle race going around 60-80 mph. I remember the guy passing me and pushing me off the track, seeing the tire barrier and then going down, but the next thing I remember is seeing a beautiful blue sky and realizing I'm in a golf cart with a corner worker telling me "I think you should see the nice men in the ambulance". I know I was up and about because I had taken off my helmet, gloves and earplugs and pulled my leathers pulled down to my waist. Only I could have done that because the corner workers won't touch you if you are down, they would never take off your helmet.
To this day I have that gap in my memory.