The working set: slow and relocate the internal voice (submodality work — a slower, quieter, further-away voice is less compulsive), dissociate from the loop (watch it run instead of running it), and set a physical pattern-interrupt paired with an externalised task. Compounds with ordinary sleep, movement and journaling hygiene.
Clinical anxiety disorders and compulsive rumination that impairs functioning need qualified support — this is the kitchen-sink variety.