Birds do not worry, but people do. Even when things are good we find something to worry about. I am sure no one but me does his. We just need to trust Jesus. Here are some great Bibles verses on anxiety and worry.
Matthew 6:26-27 Look at the birds of the air, for they neither sow nor reap nor gather into barns; yet your heavenly Father feeds them. Are you not of more value than they? 27 Which of you by worrying can add one cubit to his stature?
Matthew 6:33-34 But seek first the kingdom of God and His righteousness, and all these things shall be added to you. 34 Therefore do not worry about tomorrow, for tomorrow will worry about its own things. Sufficient for the day is its own trouble.