Sorry about the thumbs down..I miss-clicked. Thought I hit thumbs-up! Have you ever tried to pattern-breathe? When my thoughts get stuck in an obsessive loop, it sometimes helps to take moderately deep breaths in a pattern: mine is 4 to inhale-hold 2-exhale 4-hold 2 and repeat. The pattern shouldn't be a strain, but it should be just enough outside of how you normally breathe that you have to concentrate to hold it. It doesn't always work to calm me down, but it does work more often than not and tends to pull me out of the "what if" loop. Good luck.