Could i have a consussion? what should i do?

i'm 15 years old i was in p.e at my school and we were playing a game, one guy on each side of an exercise ball and u run at it and try to get it to fall on the other person's side ("sumo wrestling") and i ran towards it to try to use my shoulder and my head hit the other kid's side and he's skinny and boney. it hit the top of my head yesterday at around 2pm in the middle of my head but i have neck pain and i'm somewhat dizzy still and sleepy random parts of my head hurt and i have a small bump. what should i do? could it be a concussion? i went to sleep last night but it still hurts