Best to be safe and have it checked out by a doctor. They would need to take a picture to see if you have any problems, like internal bleeding that could later become very serious if not treated early. Here are the warning symptoms of a possible brain injury (concussion):
- Loss of consciousness, even if only briefly
- Any period of amnesia, or loss of memory for the event
- Feeling dazed or confused
- Headache
- Vomiting
- Seizure
The odds are low that you have one, but I would not risk it. Just get checked out to be safe.