Matthew 6:34

Do not worry on tomorrow, for tomorrow will worry about its own things.  Sufficient for the day is its own trouble.

Worry gets ahead of God and creates problems where there may not be any.  We need to stay in the day that we are in and not let thoughts or ideas the enemy throws at us come into our mind.  If the enemy can get us to worry over something we are not praying to God about it.  Peace begins with faith in Jesus and that He is with us to help us in our times of adversity.