How can you tell if you have concussion?

Today I passed out and hit my head when I fell. I saw a doctor after and they didn't mention anything about concussion. I also haven't really been showing symptoms, other than a headache. But, I hear than it can sometimes take days for symptoms of concussion to show and given how hard I apparently hit my head (I don't remember it as I'd blacked out) I'm kind of worried about it. Is there any way of telling if you have it? Should I be worried?

[Dr. Kokil Mathur]

Hi  forevernever
Welcome to the MedHelp forum!
A concussion can last for weeks after the head injury. The symptoms too vary from person to person. Headache, confusion, memory loss, dizziness, nausea vomiting, slurred speech and fatigue are common. Delayed symptoms include depression, irritability, sleep disturbances, seizures, loss of smell etc. A doctor generally looks for focal neurological or generalized neurological symptoms that would show there is a pressure on brain somewhere. In absence of these symptoms and based on the history a diagnosis of concussion is given.
Hope this helps. Do discuss this with your doctor and get yourself examined. Take care!