The past has gone. Sure, forgiveness and amends are necessary before it can be let go, but let go it must be, if I am to be happy.
If you have a tricky international journey with delay and difficulties, when you arrive at the destination, the task is to make the most of being there. You put the journey behind you and get on with it.
Similarly, the arduous past is the journey to a position from where I can be helpful to God by being helpful to others. I'm here now. No need to dwell on the past or wear it like a badge.