Don't fret or worry. Instead of worrying, pray. Let petitions and praises shape your worries into prayers, letting God know your concerns. Before you know it, a sense of God's wholeness, everything coming together for good, will come and settle you down. It's wonderful what happens when Christ displaces worry at the center of your life.
Summing it all up, friends, I'd say you'll do best by filling your minds and meditating on things true, noble, reputable, authentic, compelling, gracious—the best, not the worst; the beautiful, not the ugly; things to praise, not things to curse. Put into practice what you learned from me, what you heard and saw and realized. Do that, and God, who makes everything work together, will work you into his most excellent harmonies.