I've tried napping throughout the day, but that only made me tired. I've also tried going to bed only when I'm too tired to stay awake any longer, but that didn't have much effect.

The only thing that has worked is having someone sleeping with me to wake me up if I'm having a nightmare, but I can't exactly do that every night. [Since he and Kohan live in different houses, and Colonel spent most nights in Tear's room.]