It is so easy to get into a spiral of ugly thinking. You have to stop it before it takes over your life. Practice Paul's advice to the Philippians it will make your life so much better.

Philippians 4:8-9

Finally, brothers, whatever is true, whatever is honorable, whatever is just, whatever is pure, whatever is lovely, whatever is commendable, if there is any excellence, if there is anything worthy of praise, think about these things.
What you have learned and received and heard and seen in me—practice these things, and the God of peace will be with you.
Bible Gateway Link: Philippians 4:8-9 (ESV)