How can you move forward when you are stuck in the past? The past can't come back. So, why waste time and energy in the past? By wasting energy in the past, you destroy the potential you have in the present reality and future you.
Never worry. Worrying is the process of looking at the past (subjectively) to predict the future.
Though we all worry, it has a major flaw. Worrying has never solved one problem in your whole life. All it ever does is let your imaginations run wild, over a possible future, that possibly will never play out exactly the way you imagined.
Study the lessons from your history, learn from your mistakes, but leave the past in the past.