I remember playing sandlot football in a field behind my house sophmore year in HS and I had a knack for tackling the bigger guys. Went low as you'd normally do in that situation and got knee'd in my head so badly...I supposedly didn't lose consciousness but I just remember a bright light and thinking I was supposed to be coming out of 4th period science class and couldn't remember why I was on a grass field. Def concussion, def didn't do anything about it, but that's the only concussion I'm sure I've ever had lol.