What self-help books or exercises actually helped you reduce overthinking at night?

I’ve been working on a short self-help ebook about overthinking at night and calming mental loops.

While putting it together, I got curious: what actually helped you in real life?

Books, exercises, journaling, breathing methods, mindset shifts… anything.

I’d genuinely love to learn from what worked for others.

If anyone wants to see what I made, I can share it in the comments.