That happened to me when I was coaching a few years ago. Got hit on the head while on the bench twice within a couple weeks. After second, woke up the next day with room spinning and it wouldn't stop. Wife and son had to help me into car to go to ER. Had Vertigo, and had to stay in bed for a couple days. It took over a month before I felt normal. But I still play hockey, and the occasional bump to the head still makes me dizzy.