The Other Night I Left A Bar To Meet Up

The other night I left a bar to meet up with some different friends down the street and I was intoxicated, but not to the point of falling down or blacking out. I remember walking out of the bar but then the next thing I remember is being in an ambulance with a gash on my forehead that needed 14 stitches. I also have two black eyes, scratches behind one ear, scrapes on both elbows and knees, and bruising on my dominant hand. Is it possible that a physical altercation occurred and a punch or elbow to the face could have opened up my forehead like that and caused me to completely forget the trauma occuring? Or is it more likely that i tripped over something and hit my head?