It's recommended that you get checked out anytime you've been in an accident so that potential head and brain injuries can be diagnosed quickly. Some common symptoms of head or brain injury include:
Dizziness
Nausea and vomiting
Confusion
Depression or irritability
Headaches
Losing consciousness
Feeling numbness in any body part
If you recognize any of these symptoms, they shouldn't be ignored. Visit a doctor to be on the safe side, and make sure to request copies of all medical documentation. (This will help if you decide to file a claim later on.)