Hit my head at a concert, should I get it checked out?

I was at a metal concert last night, and around 8:15 a bunch of people pushed back into me, and that caused me to hit the side of my head on (I think) someone else's head. It didn't hurt that bad, and I don't think I got a bump or anything, but today my head hurts a little bit and I have pressure in my head (don't know if this is just my allergies or what). I'm worried about it, since I heard about the Natasha Richardson thing and how a 7 year old girl got hit with a baseball and only had a small bump that went away fast, and then she felt fine for the next two days and then got a headache 2 days later, and turns out she had brain bleeding that would have killed her. I didn't hit my head that hard, but should I get it checked out? How hard do you need to hit your head to where you should be worried about getting it checked out?