Twilight jumped out of bed, gasping for breath, her blanket getting caught in her flailing hooves. She could still feel the broken ribs; expected still to feel her life drain from her. But as she stood, all four legs replied that they were whole, despite her expectations. Warily she flared her horn. Left the light at maximum. The spare bed was freshly made, just there. Her telescope near the window, the curtain pulled tightly shut against the night. Silently she vowed to apologize to Luna; clearly this was not her doing.
She limped anyway, the psychic damage too fresh in her mind as she went to the balcony. Her fancy wall clock said it was a few minutes past one in the morning. Stepping outside she felt the cold air shock her senses into the here and now. It had been a nightmare. From the past week she knew that if she tried to go back to sleep, the shadowy figure would return immediately. The setting and his weapon changed each dream, but they were getting darker and meaner every time.
But if she waited at least two hours, then she could sleep but not past daybreak. If she overslept the figure would give her a vision of he beloved mentor, ruler of all Equestria, burning. Or rotting. Or sometimes insane, killing everypony while her student watched in horror. The nightmare mightcontinue for months within the dream, before finally she gave up, and found a way to die.
That would wake her up.
Which was the real world? She was exhausted enough that it was starting to get difficult to remember. She was afraid someday she'd mistake a badly decorated room for a nightmare, and kill herself for real. She'd finally get the sleep she was losing, of course. But she'd never wake again, either.
Closing and latching the door against the winter chill, Twilight walked as calmly as she could manage to the kitchen, and made warm milk & honey to drink while she waited out her allotted time.