I just accidentally hit my head on the concrete wall behind my bed and now I'm dizzy, have a headache.?

Could be serious. Sometimes an injury like this can cause intracranial bleeding or injury. You need to get checked by a doctor immediately. Also, make sure someone stays with you and checks hourly to make sure you are alert and easily arousable with no worsening of symptoms.

Related Questions

I fell down a flight of stairs and hit my head on concrete. I have a mild headache, a little dizziness but no nausea or pupil dilation.

Neuro. If you had a loss of consciousness then you should be evaluated immediately at an emergency department. If headache increases especially if associated with increased nausea or vomiting call 911 immediately. Otherwise, continue to monitor and you can take tylenol (acetaminophen) for headache and rest for the next day or so. Read more...