sex with the devil
The way she rolled and held her blanket, it was obviously clear something was wrong.
For a moment, she calmed down. And not quite long, she started rolling again until she woke up, gasping for air. This time, she wasn't in hell, but what actually happened in her dream was worse than visiting hell itself.
She went to the bathroom to ease herself, on passing the mirror above the sink, she saw a figure standing by the door. She turns to the door but there is no one there, but when she looks at the mirror, there is someone standing by the door.