My interpretation, and also why I don't subscribe to the claims of the season having a happy ending, is that it was a function of the house luring her back. I assumed it was her trying to warn herself at first, too, but it isn't like they ever communicate. She's just being scared to death. Those scares just lead to her going back to the house in hope for a resolution, being taken under its influence and, killing herself. It gets even more morbid when you realize the wife manipulates her husband into killing himself to save his remaining children. It's painted as a "happy" ending but it's really not
I read the original ending had the red door in all of the future shots showing they never left. The creator decided to change it.