I'm new astral projection and I recently tried it. After I was relaxed and in the meditation state I tried to lift my spirit out of my body, but when I did I felt like I was shrinking and growing really thin. Also my view of everything was covered in black, gritty, spots. I probably just ended up failing (it's only my first try :P) and this was how my mind reacted, but I'm still wondering if it means anything at all.
I wish you luck, and honestly, I don't think it means anything except for a failed attempt at AP. I know my first successful AP everything was quite dark and gritty as well, but people report a number of things from buzzing noises to other random phenomena.
Im not expert on the subject though xD so best of luck.