A Dream About Just Falling?

This is a dream I had in middle school when I fell asleep during class. I think I was sitting by the window. In a way, it was the most impactful dream I've ever had. I was all alone in a completely white space. Soon after I started walking, I began to jog lightly. As I was running, I felt like I was about to fall and tried to roll, but without any sensation of impact, I just kept sliding right before I probably hit the ground? ○ー<　==　←Me ______ ←Ground? Can't see it because it's white After sliding for a while, I suddenly fell. From the rebound of the dream, I headbutted my desk in reality. I remember the teacher's surprised face and my deskmate laughing so hard they were in tears.