rocks in my head

For the past 24 hours, I've had a headache and a bit of vertigo. It all started on my birthday. Here's the stupid story:

I went out to the driveway to chop up some of the last bits of ice (our driveway faces north). I was using a regular shovel (not a snow shovel) and was just kind of jamming the shovel into the ice and then scooting it away. WELL, I jammed it down once and suddenly had a headache. In fact, I got a little nauseous. For the rest of the evening (and the whole next day), I had bouts of vertigo.

THIS IS AN OLD PERSON'S INJURY, ISN'T IT! How does one give herself what amounts to a concussion - or some stupid thing - just by jamming a shovel into the ground??? I'm so embarrassed!