Do i have a concussion? i think i have a cuncussion but im not sure. i hit my head really hard on a door knob and im pretty sure i blacked out for about five minutes also i feel really dizzy and its hard to look at the computer also i have a large lump on

You : You may have a concussion. I recommend that you be medically evaluated for your symptoms.

Yes: Any loss of consciousness qualifies as a concussion. No loss of consciousness with the dizziness you describe would qualify as a concussion. If symptoms do not resolve spontaneously or if symptoms worsen, you should seek a more formal evaluation. Good luck