They are correct in the sense that this is not Astral Projection. It is simply either an Out of Body Experience that is happening subconciously (which you might want to look into what might be causing you to do this, because the idea of sleep walking out of body is definately not good) or it could be a very vivid dream state, that gives you the feeling of "jumping" back into your body. This is common with people who delve deeper into thier own subconcious during sleep than normal. If you wake too fast, your mind must "yank" itself back to reality, causing your body to jolt as your now suddenly concious mind takes control back over your body. Anyways, hope this helps. Take care...