What does your anxiety do? It does not empty tomorrow of its sorrow, but it does empty today of its strength. It does not make you escape the evil; it makes you unfit to cope with it when it comes. God gives us the power to bear all the sorrow of His making, but He does not guarantee to give us strength to bear the burdens of our own making such as worry. Ian Maclaren.
Jesus spoke directly to this issue in Matt 6 25:34, this is our subject, How to deal with worry.