Worrying about things, reminiscing, reviewing bad things that happed through the day or even thinking about what you still have to do, can cause problem sleeping. Negative thoughts about sleep also make it very hard to fall asleep ( i.e if I will not sleep again tonight, I definitely will not be able to work tomorrow). The fear of not falling asleep causes anxiety, which increases bodily arousal, the heart starts racing and muscles become tense. The physical discomfort creates worrying, restlessness and even more negative thoughts. As a result it becomes very hard to relax and fall asleep.
What can you do to improve it?
if I will not sleep again tonight, I definitely will not be able to work tomorrow