The event of today (this is real)

I was walking from my living room (which was fairly brightly lit) to the bathroom down the hallway (the hallway was very dark compared to my living room) and as I was walking my eyes were taking longer than usual to adjust to the light change, then the next thing I remember was that I was on back on the floor, having just fallen. So I blacked out for a few seconds because I don't remember myself falling at all. I'm fine now though except my left elbow got cut and that arm hurts if I move it too quickly and too much.