Could I have Schizotypal Disorder?

Your symptomatic profile is rather inconsistent with the criteria for schizotypal disorder or other pre-psychotic conditions, wherein hallucinogenic experiences or delusional preoccupations are the hallmark concern. Rather, given your acute dissociative states, I would be more inclined to diagnose the problem as perhaps a consequence of a derealization or depersonalization syndrome. The out-of-body experiences you describe, as well as the incessant doubt of external existence are routinely recorded by patients who suffer from these conditions or related fugue states. Hence, subliminal anxiety may be the culprit perpetuating such symptoms, however you do not illicit any probable stimulus to be a source in your post. Regardless of the etiology of your malady, I urge you to seek clinical intervention by speaking with a licensed psychologist. Only a trained professional will be able to render a diagnosis and treat the problem accordingly.