Yes, it's hard to let the past stay there, but trying to live for the future is hard too.
That's why, just being satisfied that the present is all you can make it, should be sufficient for anyone.
I do what I can for the now, and wait for the future to take care of itself.
Life is short. So just Enjoy the now.
It's all you're promised anyway.
Besides, you'll have a lot more fun, without all the worry.
Try it, You'll see........