universal hum??

Hi, Since reading Astral Dynamics I have managed 11 astral projections to date. I intend to share them eventually but as they do not require an answer I'll move them somewhere else.
However, a couple of questions relating to my latest.
After the vibrations and still awake (I hadn't gone to sleep) I did my usual flitting downstairs holding the railings at first just incase I broke my neck. Pleased to see it was real and I floated downstairs, into the other rooms but it was dark and uninteresting so went back up to the bedroom. Not wanting to waste this experience I decided to project up to the sky.
I don,t know how or why but I was travelling flat on my back.I was ,best described as cocooned, in a bubble of mist and could hear a loud buzzing noise.I was travelling slowly upwards passing through different shades of grey mist (or cloud) In the distance I could see stars but there was too much grey in the way.This is the first time I've been a little scared so I returned back to my bed, opened my eyes and wrote some notes.
My questions are.
What was the mist around me?
How did I end up on my back?
What was the buzzing noise I was hearing?
( A couple of weeks later I read that scientists have proved that the universe has a hum to it resembling the note B . (Deepak Chopra).
This noise was like a bumble bee buzzing.

Would appreciate any advise you could give me on this.
Susan