There isn't really a point in thinking about the past anyway. It has no influnce on the future. It only influences the future, when you recreate it in your powerful now. You can just choose to no longer think about the past and shift your thoughts to different things.
"Self-abandonment. That is the secret. We have to abandon ourselves to the state, in our love for the state, and in so doing live the life of the state and no more our present state. And to make the state alive, one must become it."
Neville Goddard ~ The Law and the Promise