Don't worry about anything; instead, pray about everything. Tell God what you need, and thank him for all he has done. Then you will experience God's peace, which exceeds anything we can understand. His peace will guard your hearts and minds as you live in Christ Jesus. — Philippians 4:6-7
This is one of the best "calm me down" scriptures that I know and it has to do with prayer. It reminds me to let God do the worrying when things are not working out very well. Perhaps it will become one of your favorites as well when you feel your stress level rising.
In another place Jesus said this about worry: "So do not worry about tomorrow; for tomorrow will care for itself. Each day has enough trouble of its own." (Matthew 6:34) Uh, oh, you mean that trouble is likely to come tomorrow just as it did today? Well, that's what Jesus said, but He also said, "Don't worry! PRAY."
Perhaps you remember the old Greyhound Bus ad that ended with, "So leave the driving to us." Jesus is telling us when it comes to worry, PRAY and leave the driving to Him.
Corporal Jacob DeShazer was one of the men shot down over Tokyo in the famous Doolittle raids of World War II. On the night of his capture, his mother, being extremely worried about her son, felt compelled to pray even though she had no idea of where he was or what he was doing. She said,
"I awakened suddenly one night with a strange feeling like I was being dropped down, down, down through the air. Oh, the terrible burden that weighed my soul! I prayed and cried out to God in my distress. Suddenly the burden was gone."
She later learned that at that precise time her son was parachuting from his falling plane. After his capture and imprisonment, his mother again felt compelled to pray for her son. It was later learned that at the precise time, God spoke to Jacob in his prison cell and he surrendered his life to Christ. Soon after, it was announced that all prisoners would be executed. His mother cried to God to watch over her son, and again her intense burden lifted. Jacob was soon released.
God didn't just save DeShazer's life, he saved it for a purpose. After the war, he returned to Japan and spent the rest of his life preaching Christ to the Japanese people.*
*Alvin J. Vander Griend with Edith Bajema, The Praying Church Sourcebook, Church Development Resources, A Mother's Prayer, p.249.