OBE

Today I was meditating and believe I experienced an OBE. I was aware that my body was there, but I felt as though I only existed in consciousness. Everything was black. In the process of reaching this state my body started twitching uncontrollably. My eyes & hands & arms especially. After a time I became frightened & stopped the process. It feels as though I am barely breathing. Is this a normal response? I have been using the Hemi Sync Global Meditation for this. Also, when you experience an OBE aren't you supposed to be able to travel to different places, or does that come with experience, or is each individual's experience different? After the meditation I feel so weak. Any feedback is greatly appreciated! Also, just wondering whether it is better to meditate in a dark room or, say, outside in the sunlight?