I am not a big fan about dwelling on the past. Look at it, accept it, learn from it and move on. Try and do something just a little thing positive everyday, set achievable positive goals and work towards them and achieve them. Over time, you will find that you will accept the past for what it is, the past. You will see how all of the things that happened in the past will have contributed to who you are and though you may not be proud of some of it, you would not change it as it is part of the path it took to become the person you are.