Coincidence?

I went to boot camp as usual this morning. Our trainer, Nathan, was instructing my partner and I on improving our over-head throw technique. My partner threw the ball when I wasn't looking and it hit me on the head. Luckily it was only the 2kg ball today so it didn't hurt as bad as the 4kg ball we usually use would have hurt. I was definitely caught off guard and surprised when it hit me!

Now that I'm home, I'm feeling a little dizzy and light-headed. So is that purely a coincidence (since I'm always a little "dizzy") or is it cause and effect?!? :)