Worry splits into regret about the past and anxiety about the future, both unproductive. Extract the lesson from mistakes, then release the guilt. Plan for what's ahead, then focus on execution instead of fear. Let go of both and you can actually live now.
Stop worrying. There are two major kinds of worry out there. One is regret over things you've done in the past and thinking through, oh my goodness, all that stupid stuff I did. Idiot, idiot, idiot. I think we've all been there, right? And then there's a second version, which is a thing that might be coming to pass that is just over the horizon. The demons right there are just around the corner. Neither of these are helpful to you. It is helpful to think strategically about what might come, but then once you've got a plan, you just need to execute on it. And it's definitely not helpful for you to be kicking yourself over things that have happened in the past. The key is to look back, take the lesson, and then put it down. It's like thanking the memory or the experience for its service, because it's part of the journey that has made you the better person that you are today. That can feel a little self-serving, but it is. But there's not more that you can do about it. If you stop worrying, if you release yourself from the guilt of the past, if you don't go after the fear of the future, you can live in the moment and succeed.
