Yeah, go to the fucking ER. Or now that it's a weekday at least call your regular doctor and get an appointment ASAP.
A concussion can last longer than a day, even sometimes longer than a week. You might feel okay now but just wait for the wave of nausea and the headache that will hit you every couple hours.
Also, like the guy was saying above, you NEED to be extremely careful with a concussion. I'm on week 2 of my concussion and I still haven't done hardly anything because of Second Impact Syndrome. You would learn about that if you went to the doctor. Basically it means if you hit your head again with a concussion, there is a high chance you can die. In the matter of minutes.
Don't be an idiot, go to the ER and get your head checked, which means a CT scan.
Do you remember Natasha Richardson?
http://www.msnbc.msn.com/id/29733775/
If you can get yourself checked out, do it. And don't let money steer you away from getting a head injury treated, that's ridiculous.