I had a pedal axle snap off as I was accelerating quite quickly through an intersection. I figure I was going about 35 kmph when it happened. I wasn't expecting it and all my weight shifted and down I went. I landed on my hip and my neck snapped back so I hit my head on the ground very hard. I was wearing a helmet and I figure it did me a world of good. I was pretty bruised and I had a hard time turning my neck for a few days. I also had to get a new helmet as my old one was all cracked up but in the end, I was even more convinced that I should be wearing a helmet at all times.
I would suggest that if you are going to travel at any rate of speed, you should have a helmet. I was just in Zurich and there are bike lanes and bikes everywhere and far fewer people wear helmets as compared to here in Ontario but they likely also have more o0f a biking culture and cars are looking out for them.
In any case - I am certainly pro-helmet...
Glad you are ok.