Karl Gustel Wärnberg writes on the theology of sleep:

The first reference to rest, which is not the same as sleep, is Genesis 2:2, stating that God rested on the seventh day. God did not rest because he was tired, for that is impossible for God the Father. He rested for two reasons: because he was done bringing non-existence into existence, and because he was satisfied with what he had created. As humans we cannot create something out of nothing. But we can create, and be pleased with what we create. After a day’s work, we may be pleased with what we have managed to achieve. And so we may rest. For us, rest is associated with sleep, which allows us to resume our work later on, and create more satisfying achievements. …

Sleeping is an act of faith. Every time we go to bed, we entrust to God that we will wake up the next day. Every night is an anticipation of the day when we will never wake up again. …

When we go to bed, therefore, it is a Christian custom to make an examination of conscience. We ask Almighty God to help us see what we have done well, what we have done badly, and what we could have done better. We ask the forgiveness of our sins, and may make a special resolution for the coming day, if God grants us the gift of another day.

If you’re going to sleep unsatisfied or anxious, it might be a signal that you’re not spending your time doing the right things.