The speaker describes what seems to be a dream: she sees her own house and a person she addresses as "You" in the window, who looks at her with disgust and walks away. Then the room shifts, and she is the one at the window, looking down at herself. That reversal prompts an uneasy question: is she a hypocrite for judging the girl she used to be, or for judging herself at all?
The middle of the poem turns to fear. Monsters, snakes and guns don't frighten her. What does is the other person's face, especially the false look of concern they put on. The ending is the bleakest part. She tells herself to wake up, and the only answer is "But you're already awake..." The nightmare isn't a dream at all. The mood is eerie, lonely and quietly painful, and the poem suggests that being hurt by someone who pretends to care can be scarier than any imagined danger.