Astral projection

Several days ago I bought the DVD "5th Dimension", episode "Life after death". It's a documentary movie about near death experiences. Two years ago I've had a short out of body experience. It happened spontaneously while I was slumbering on the sofa in my grandmother's apartment, at my birthplace, Zenica. I wasn't sleeping. In a moment I was 1,5 meter away from my body, watching it from the distance. I never experienced anything similar before, so I was very surprised and also a little scared. I asked my self if maybe I was dead. I knew that it is what is called astral projection but after five seconds I desperately wanted to go back into my body. While entering it, I noticed something like a membrane, which was not visible, something like a magnetic field. It was like if I was entering a balloon from the outside. When I returned into my body, I was fully awake and very happy because I experienced it. I wasn't able to repeat it. That made me sad. I shouldn't have returned so fast.
I wanted to share my experience, that's why I'm writing about it, hopeing that there are people able to explain it, or someone else had an astral projection in the past.
In that documentary movie there is a painting by Hieronymus Bosch called The Ascent of the Blessed. I was reading about the light at the end of the tunnel as described by some people returned from the clinical death. I hadn't seen anything like that, nor I felt the presence of Angels or any kind of spiritual stuff. I was completely alone with my self. It was a very natural experience.
I was reading Rudolf Steiner's books for many years, and he described subtle bodies beyond physical, and these are etheric body, astral body and I.
As far as I can remember, during sleep astral body is disconected from the eteric and physical body and when one part of astral body connects with etheric, we are dreaming. When all is connected, man becomes awake. If you want to know more about Steiner, look the books section in my Zaadz page and click these links: http://rsarchive.org and http://books.google.com.