After reading a bit of the book, from what i have read " the overture", i think its him the narrator talking about his past, and whilst he is laying in bed he has visions/ flash backs from his past, and sometimes his imagination gets to him and he starts to imagine scary things about the room.

in the first chapter its alot about his mind and what he can remember.

i find it hard to make sense of the book as the story gets deeper, i start to lose track of where he is in the story.