throw it in the spoiler tags breh
Ok aside from depression, it's also a metaphor for guilt and just the craziness that comes with being a single parent, specifically a single mom and the pressures that come from it. When she eventually snaps and succumbs to the monster, it can be her just as easily snapping and succumbing to the pressure and trying to figure out what to do. When she's dead tired and the kid comes in her room just asking her for food and you can see that look on her face? Man, that's tough and scary in itself.