Paranoid Secret

What is your worst nightmare?

Is it a dream of a ghost chasing you to death? A pervert asshole trying to rape you? Falling from a tall building? Drown in the sea? Losing someone you love in the most tragical way? Being impotent or frigid? Losing a part of your body (eyes, legs, arms, etc.)? Or what?

Well, my childhood worst nightmare was:

I didn't know if I was standing or sitting or laying. I couldn't see any light, at all. It should be the eternal darkness. I tried to use my logic and told myself that I SHOULD HAVE BEEN able to see some lights going through my pupils, no matter how dark my room was, from the small ventilation windows above me. But I couldn't. see. anything.
There was no ground. Or floor. Something where I could step my feet on. And nobody was around, either. I was all alone. But I was not afraid of the loneliness. Nor the dark.
The only thing that my senses could say was there was a sound. A very distinct sound. From afar. It was a sound of a hard thing banged on a hard ground.

Bum.
Bum.
Bum.

At first I thought it might be a good thing that I was not the only one in that multi-dimensional world. But my mind said the otherwise. I was in a danger.

Bum.
Bum.
Bum.

The sound was getting louder and louder as it approached me.
Even faster than before.

I tried to run away. But I couldn't. How could I? There was no ground!!!
I tried to roll myself.. in case I was laying down. But I couldn't either. No ground!
I panicked and tried to move every single part of my body. But they were actually numb. I couldn't feel them. I couldn't move them. I couldn't command them as I pleased. I couldn't do anything with myself!

Bum. Bum. Bum.

Bum. Bum. Bum.

Bum. Bum. Bum.

Then I woke up. Just before the thing, which must be very huge, fell on me.
Before I died.