I hit my head against the wall?

I have a BS in Biology, and I am an EMT. There are no guarantees; there may be something wrong even after a small bump like that. If all you have is a simple headache, I wouldn’t worry too much. One main sign of a concussion is nausea. I can’t tell you not to go to the ER because I'm not magic and I don’t know for sure if any damage was done however I doubt they will run any tests and they will tell you to come back if you show any additional signs. Relax, take a deep breath… I'm sure you’re fine