The Voice of Atma

I have been meditating for quite sometime but in the last few months I have had an unusual experience. I go very deep within – so deep that I am not there. I am totally unconscious of myself. I then hear my own voice speak. I ask questions before getting into that state and my own voice gives me very unique replies. My voice is all knowing. omniscient and wise and gives me specific directions.
When I get out into normal layers of consciousness from meditation, I feel very tired and a little drained out. But I recover soon.

What type of meditation is this? Is the voice I hear that of my Atma? And why do I feel tired?