I hit the top of my head on the counter yesterday when standing up quickly, I'm not dizzy, no blurred vision, pupils the same size, no nausea, but I have a headache and the top of my head and scalp is pretty sore. I called the nurse yesterday and she asked me a couple of questions about how I was feeling and recommended home care. Could I have a serious brain injury, concussion, bleeding or swelling, when do I know if I need to go to the ER?