So you're telling me that you experienced something like nothingness?

Something like that but it is hardly empty or nothing.

Maybe something like -- the essense of breathing?

There is an essence of sort that generates the energy to breathe and make the heart beat.
It is an outer manifestation of the lifebreath or Prana that breathes life into movement, the consciousness that drives desire, but I am talking of the home of that consciousness for that is the essence for a lack of better words or descriptions of it and all other outer manifestations.