When i was 2-5 yrs. old i would get out of body experience dreams. it felt like my mind was awake and my body was asleep. what was the cause of this?

Nobody understands: These remain a mystery of brain function -- or perhaps something beyond brain altogether, if you credit accounts of esp that go with them (i'm reserving judgement). There was a study in the 1980's jnmd that people reporting these do not have any more psychopathology / mental health issues than their peers. Accept that life still holds many mysteries -- and perhaps be glad!