Thank you Erin and Yukio for your responses,
I did think it was bordering on some kind of projection, but I felt scared that I might disappear altogether or die - the vibration was so strong!
Also, before falling asleep when this happened, it was like my mind was trying to 'drag' me into sleep before I was ready - like I started to dream while still awake. "You probably were experiencing dual consciousness as well, which is when your physical eyes are closed but you can see with your astral eyes. You can feel your physical eyes are closed but you can still see.
I think you may be right - at the time it felt so real like I was fully concious - but i probably wasn't. Now that its the day after, I don't remember it as well as when I first woke up and told my husband about it!
I will read your story, Erin, thank you!