Your thoughts won't stop on their own. So these rules stop them for you.
Your thoughts are like a demon that won't stop — rearing their head every few minutes. This is priority above everything else right now.
Three physical culprits making it worse: caffeine, lack of exercise, poor sleep. Fix the first two and sleep follows.
Write out the absolute worst possible outcome. Play it all the way through. See it clearly. Then ask: could you survive that? Usually yes. The thing you're dreading almost never matches the reality you'd actually face.
Tick each rule you stuck to today. Your progress saves automatically.