Did I do everything right?

[Major Tom]

...

[AngelicSaiyan]

I was sitting in the car during lunch today at work, and I decided to try an OBE again.  What I did, was I concentrated on my breath for like 10 minutes after I shut my radio off, and my body started to feel like it was solid and blending with my surroundings.  After that, I felt all shivery after I started experiencing REM.  I almost felt like I was on the roof of the car as well.  Actually, for a split second--now that I mentioned it-- it did feel like I was on the roof of the car.  After I snapped out of it, I felt like I was hit by a truck.  I'm asking if I did everything right.  I would love to have a "dissociative session" as my psych teacher put it.