Stress can be caused by many things. You may have taken on more than you can adequately handle, you may be in a bad work situation, or there could be tensions at home. If you truly put yourself in God’s hands and trust Him to guide you, He will show you what to do to relieve stressful situations to the extent that is practicable. Beyond that, stress is overcome through taking God at His Word and trusting in Him.
"Thou wilt keep him in perfect peace, whose mind is stayed on thee: because he trusteth in thee."