I don't know which movie it was from that one of the characters said, " I think we have two lives. The one we learn with, and the one we live with after that." And that just means that you should live without regret, as if you have two lives. This is a psychological trick that requires you to separate your regretful thinking from your regular thinking. It's sort of an easy Scientology like approach. Or you can look at it philosophically: all values are inherently illusory. This is because it is impossible to entirely know your own mind or your will. Free will can be considered an illusion of the mind. (This is a neuroscience approach.) But more importantly, the fundamental values of life may come down to no more than living in symbiosis with the earth. If that's the case, nearly all of modern life is a web of false values. All we may really get is the chance to see the sunrise, walk on the earth, eat its plants, reproduce and live tribally. Beyond that its all extra. So your world view can really save you.
Then there's religion. Essentially you can replace all your regretful thoughts with prayer. It works for a lot of people. Buddhists basically reject all desire, and therefore most regrets. That's a tough way to go.
Some say that once you have glimpsed the infinite in yourself, that this life then looks relatively insignificant. So you can rejoice in that.
Thank you Dixon for your insight. I am not really a religious person, so that is not practical for me. But I love what you said here:
"Some say that once you have glimpsed the infinite in yourself, that this life then looks relatively insignificant" - that is brilliant! thanks for sharing it with me.