Hi, I'm 18 Years Old And After Some Heavy Drinking

Hi, I'm 18 years old and after some heavy drinking after which my memory has failed. I apparently had a fall and injured my head there was some bleeding which my friend took care of. There is only extremely minor pain when I touch the injury and I feel lethargic which I assume to be from my hangover. I have not vomited and my motor functions are fine as I was able to walk straight and ride a bike safely. Where do you think I should go from here?
Thanks for the help.