I had my first wreck in ~10,000 miles of commuting and really went down hard. Totally smashed my helmet which made me pretty glad to have had it on.
I was moving pretty fast at ~18mph when I was taking a hard right turn onto a side streen on my normal route. The storm drain had backed up over the weekend and left a slurry of mud and gravel across the road apron. My front wheel started to wash out and I was sliding a bit. It felt like the bike was going to slide out from under me.
Suddenly as I rolled / slid past the muck the front tire bit really hard on the pavement and I pivoted over to my left so fast I scarcely knew what hit me. It was a classic 'high side' take down where my body was pivoted over left to slam down on the ground. I made contact entirely with my left hip and my head. The helmet was smashed, the outer shell totally fragmented and the styrofoam crushed. The whole thing took about a half second.
So the damage is a massively bruised left hip and thigh which I can hardly walk on and a totalled helmet. I can't imagine how bad a head injury I could have gotten. Plus I lost a couple batteries from one of my blinkies. I didn't even scratch the paint on my bike.
Glad you're Okay. I wish our more stubborn "Oh It can't happen to me... Oh I look stupid with a piece of beer cooler on my head so I don't wear it" brethren would take heed. You can only recover from a brain injury up to a point. Those who do make full recovery are either extremely lucky or cashing in a get-out-of jail-free card from a particularly merciful and beneficent God.