When your energy is strong and clear enough you'll "wake up" astral projected. What I mean is when we sleep we lose our consciousness awareness, what we call dreams are actually small fragments of conscience about the time we spend in our astral body while our physic body rests. I had some similar experiences. It can be a lot of things. But probably some mentor helped you as an introduction to get aware of other dimensions.
Is this recent? It can happen again if you're in the same energy state.