Rationalise your thoughts. Apply logic and reason to emotion. Don't think of it as a quick fix, think of it as learning. It's a process, it takes time but it makes a difference. Don't let emotions go untethered. Don't let them haunt you unchallenged.

Give yourself a few minutes during the day to think about what is bothering you.
Then look at the different ways to fix it.
Choose the best option, just do it. Then move on from it. You did your best. Then its time to move forward and discover new exciting things to occupy your mind, to give you peace and happiness again. Let whatever it was go. Time to heal and move on...

Have you tried journaling?

Walk. A long one. Just walk

Iam sorry you’re feeling this was sometimes it’s really hard to find peace. I try to distract myself with small things or talk to someone I trust.

In my opinion, using effort to deal with those things will usually just be frustrating the issue. Entertain in your thoughts different ways of seeing it, that it's not necessarily as it seems at the moment. Gradually it would become less and less of a problem, and find, as in an exploration Odyssey other things to ruminate on.

Time. Nothing else works for me. Also changing your environment, seeing something new and keeping yourself busy. Filling your mind with other things and pushing those you don't want there away.