Oh I've been there a time or two. Drink plenty of water and if it persists (balance etc...) go get it checked out.
You don't want a brain bleeder no way to go. Then she would be pissed.
I agree Listen to Zman @Sublime one That sounds like potentially bad. I've knocked my head or had it knocked a couple times and none that bad the next day.
Funny I was just going through my med records to give the new Doc and found the discharge sheet from when I got knocked out.