The two greatest sources of fear and worry are the past and the future--remorse over the past, or fear of the future--and God's Word forbids us to worry about either! If you know the Lord, then you're His child, and you don't have ANYTHING to worry about.
Worry is a sign of fear, and fear is not faith. "Fear hath torment" (1Jn.4:18), and lack of faith can be a terrible, frightening thing. But faith in God, trust in God, gives you a feeling of rest of body, peace of mind, contentment of heart and spiritual well-being. It's faith that keeps you from worry. It's faith that keeps out fear. Jesus said, "Let NOT your heart be troubled, ye believe in God, believe also in Me." (Jn.14:1) The beginning of faith is the end of worry! If you're trusting the Lord, you know He's going to take care of you and you don't have to worry about anything!
"God hath NOT given us the spirit of FEAR, but of POWER, and of LOVE, and of a SOUND MIND!" (2Tim.1:7) So commit your way, your life, your mind, your thoughts, your time -- your EVERYTHING -- to the LORD! "Cast thy burden upon the LORD and HE shall sustain thee!" (Psa.55:22) His shoulders are broad enough to carry ANY load!