Like, real, actual amnesia, not forgetting about how intense childbirth is.

I was in an ATV accident when I was 17. Ended up in the hospital with a pretty bad concussion and I still have absolutely no memory of how the accident happened, where it happened, or why. I only have 3 or 4 memories or impressions of after the accident until I was in the hospital getting an MRI (I think) and then the picture starts coming back a lot more clearly. Anyways, it's just this weird thing about me. It kind of amazes me how the brain locks down and there's lost time, if you will, things you literally cannot recall, no matter how hard you try.

Have you had amnesia? Did the memory ever come back? How long did it take?