My Hallway

The Psychological definition:
A nightmare is a dream occurring during rapid eye movement (REM) sleep that results in feelings of strong terror, fear, distress or extreme anxiety. This phenomenon tends to occur in the latter part of the night and oftentimes awakens the sleeper, who is likely to recall the content of the dream.

My Defnition: A series of doors left unopened in a hallway. Some opened sooner than later. Some opened later than sooner. I walk through this hallway with no end in sight opening door after door. So where is this hallway? It's in there. In that disturbed mind.

But, who am I?