How can I tell if I suffered a concusion?

Head injury? Symptoms of a concussion can include a headache as well as nausea or vomiting. You may feel dizzy or lose balance. You might find that bright lights make you uncomfortable. Your vision can blur or you could see bright colors. Ringing in the ears is common. You may not think as clearly as you normally do. You can have a concussion whether you lose consciousness or not.