Fell off my bike at the weekend and banged my head on the road. Had a lump on my temple which is still sore to touch and bruised. I’ve been getting dizzy spells today, the sort where it feels like everything is spinning (like being drunk). I’m not sure if concussion can kick in a few days after a knock to the head, or if it happens immediately. Anyone with any advice on what concussion is like? I don’t have any other symptoms, just this dizziness…