How do I stop living in the past and worrying about the future?

We are so detached from reality in so many ways. We live in the past, what happened. We live in the future, what could happen. We are all over the place, but we are almost never right here in this moment, just existing with God. Everything that happened in the past is gone. It does not exist. Anything that is going to happen in our life is a mystery. We have no idea what is going to happen. The only thing we can ever do is be in the moment with God.