Ask HN: Last week I took a break from any work and I slept much better

Hi HN.

I'm a college student and I spend a great deal of time programming.

Last week, when I took a break from any work I slept much better than usually.

I think this could be the reason why I sleep bad:

When there's a problem I can't stop thinking about it.

It's not just programming problems, because I try to make some money from my own projects, and that makes me be sort of obsessive about it.

What should I do to sleep better?

Any ideas please?