The longer you live in the past, the less future you have to enjoy.
Yet we all seem to be anchored from time to time by mistakes or past misdemeanors.
There were once two monks on a pilgrimage. One day, they came to a fast flowing river. 
On the banks of the river, a young beautiful woman sat weeping because she was afraid to cross. She begged the two monks to help her. Now this order of monks were forbidden to even touch women so the younger monk immediately turned his back and began to walk away.
But the older, wiser, monk picked up the woman without a word and wadded across the river. After setting her safely down on the other bank continued his journey. The younger monk came after him, in his fury, scolding him and berating him for breaking his vows. He continued for the rest of the day reminding the older monk of the terrible thing he had done.
Finally, the older monk turned and said,. “I only carried her across the river. You have been carrying her all day.”
This is the very heart of the problem accepting what has happened whether good, bad or neutral and moving on. We seem to remain attached to these events so how do you let go.
Talking through the feelings and memories can be a good first step to come to terms with what happened. Often this works well with friends or family, yet you have to be careful for in keeping revisiting the events over and over, you feed their power over you, their power to traumatise you again, and their power to hurt you again. The focus has to be about helping you move to an acceptance of what has happened so you may choose to use a therapist.
This process of letting go is part of stepping back you may find that you have learned from the experience or even that, surprisingly, positive things have come from the experience. This is all part of the process of acknowledging what has happened and forgiving yourself.
Moving forward there are practices such as mindfulness and meditation that can help keep you focus on the moment so that you can gently move the focus from past concerns. It may also help to break past bad habits focusing on unhelpful thoughts and events.
Finally embrace the future, it may take time to work through your feelings, your relationships and let go of the toxic moments. Ultimately though the effort will allow you to let go of the past and live in the moment in a healthy relationship with the most important person in your life – yourself.