My counselor taught me that when something is stressing you out, you need to make a plan and commit to it. Maybe make a budget and a calendar for paying bills, and when you stress about it tell yourself "I am doing something about this, it is being handled, I can think about other things."
That kind of thing has really helped me. Instead of spending 15 hours a day ruminating on whatever, I spend half an hour actually doing something about it and then when I start to have those thoughts I can acknowledge that it's a waste of my energy and that things are being handled as best as they can.