You can't enjoy today if you're worrying about the past or the future

Your mind and your thoughts could be stuck in the past, continually thinking about what has already happened. If that's the case, it's best to get over it. The past has already happened; you can't do anything to change it. Rather, you ought to trust God that he is working out those things for ultimate good (see Romans 8:28).

On the other hand, your mind could be stuck in the future, thinking about what might happen, what you fear will happen, and things you wish wouldn't happen. However, being a person of faith requires trust--trusting God about the future.
Romans 15:13 says, May the God of hope fill you with all joy and peace as you trust in him. You'll have joy and peace when you trust in God. Why? Because you'll be able to rest and relax knowing that God has good plans in store for you (Jeremiah 29:11).

Don't worry about the past or the future. Instead, have faith; trust God. When you trust God to help you learn from the past and provide for your future, you're free to enjoy your life today.