Be anxious for nothing, but in everything by prayer and supplication,
with thanksgiving, let your requests be made known to God;
and the peace of God, which surpasses all understanding,
will guard your hearts and minds through Jesus Christ.
Being anxious or worried will not change anything. You need to decide what you can do to deal with the problem or situation and trust in God to take care of those things over which you have no control.
This is something you have to learn on your own. It must be experienced.