Often, we worry about things that haven't happened yet or may never happen. Worry steals away our joy and makes us incapable of completing the tasks God wants us to accomplish throughout our lives. When we are stuck in worry, our minds are occupied, making it difficult to pray and listen to God. 
Apart from God, nothing in this world is guaranteed, including our tomorrow. Of course, we all wish to see tomorrow, but there's no guarantee that tomorrow will come - only God knows for sure. Therefore, we are commanded not to worry, fear, or be anxious about tomorrow and what it may bring.
If you begin to get anxious about what may or may not happen, spend time with God in prayer. Put your focus on Jesus instead of the 'what ifs.' When you put your worries in God's hands, you will find peace.

Dear Heavenly Father, thank You for Jesus and the Holy Spirit, through whom I've been given a new life. Thank You that even though I live in a sinful body that's subject to death, I'll be clothed with an eternal body through faith in Christ Jesus. Teach me to live a righteous life like Christ and to do only what pleases You. Help me gain wisdom from Your Words so I can live my life according to You. 
In Jesus's name I pray. Amen.