Some of us live mostly in the past, letting what happened have a strong influence on today, and their identity.
If the past, or parts of it are not good, then there is a strong argument to change your habits of thinking to let it go. The first part of any change is to notice what you are habitually doing, and want to change.
Understand that the mistakes others made had nothing to do with you. And you were doing your best (and learning) when you made mistakes. It was all part of the process to make you better and stronger – if you let it.
There’s a longer answer here, but put symbols, words, and images, of who you want to be and where you are going in your environment. Change your environment, and change the words you say to yourself, even if you don’t believe them at first. Make it a point to focus on the better you, free from any past negative influence on purpose each day, until it becomes a habit – which will take longer than 30 days.
The past was events. You are not an event.
You are a dynamic human being with the power to create any life for yourself that you want.
Now go out and take it.