Isaiah 26:3 Says "You keep him in perfect peace whose mind is stayed on you because he trusts in You." Do we really trust God? Do we truly believe He will do what is best for us, or do we allow our minds to continually dwell on the problem? Philippians 4:8-9 says, "Finally brethren, whatsoever things are true, whatsoever things are honest, whatsoever things are just, whatsoever things are pure, whatsoever things are lovely, whatsoever things are of good report if there be any virtue and if there be any praise think on these things and the God of Peace will be with you."
If we have accepted God's free gift of salvation, we can trust Him to meet every need in a way that is the absolute best for us. We CAN have peace!