wakey,

You redefined my question. <Do you play any contact sports where you may have been dinged but not remember the head ding?
I've been dinged--I played contact sports--but nothing like this.>
What contact sports did you play?
What positions did you play?
How often were you in any type of head or helmet contact situations or even head jostling situations? Heading the ball in soccer? LaCrosse?

Concussion can be progressive. Small dings can accumulate so a point where a simple concussion can do big damage. Your 'ding' history is important. Even your history where you were at risk to get dinged is important. The best concussion doctors complain about the lack of collecting this kind of history.