Talk to yourself in the second person
'You can handle this' works better than 'I can handle this', and the reason is not mystical.
Do this
When you are churning on something, narrate it using your own name or 'you' instead of 'I'. Write it down that way too. Ask what you would say to a friend in this exact position, and then say that.
Why it works
Called self-distancing. Shifting linguistic perspective appears to reduce emotional reactivity and improve reasoning about the problem, showing up in both self-report and physiological measures. It seems to work by moving you from immersed reliving to observing.
Where it fails
Effect sizes are modest and this is a lab-heavy literature with less field replication than you would want. It also helps far less with practical problems that need a decision rather than a perspective.
How you’ll know
The churn should shorten. You are looking for the loop breaking sooner, not for the feeling to vanish.