puzzles! I love puzzles, and they really help me control my overthinking. part of my problem is having 1. way too much mental energy and 2. no confidence in myself, and puzzles take my overthinking brain into a lighter place.

I like real ones but I also like computer games/video game puzzles. Glass Masquerade is one of my faves, even things like 2048 are good for taking your mind off stuff, and The Room series is good too. If you're a more advanced puzzler, things like Myst might be up your alley. 

And Sudoku and Crosswords are always always good.

just wanted to throw it out there - never underestimate the power of a good puzzle to redirect your nervous energy. we spend so much time ruminating over (usually) imaginary threats, we could be using that energy in other ways. good luck and love to everyone suffering anxiety, I wouldn't wish this on anybody. but puzzles are great.