Hit my head, now there's a 'tightness'?

I hit my head wednesday when I was in a car that swerved and I was not wearing my seatbelt and flew across the backseat. I instantly had a bump on my head, and felt a bit dazed. It is now sunday and I have had a headache every day since then except today, however the bump is diminishing. I have a tightness in my head though, and it feels like it's moving back now. Should I go to the doctors?