Sometimes I feel like I've opened Pandora's box or something, and I have a difficult time realizing this life may very well be all there is...and I've wasted so much of it.
Forgive me, I don't know your story. But your statement reminded me of something my step-father told me right before his death. He had spent nearly 50 years as a Witness, elder, anointed, yada yada. But toward the end of his life he felt he had wasted it because he knew in his hear the Witnesses did not have "The Truth". He knew wasn't going to be a judge in heaven and wreak vengence on all those people who had hurt him. He knew he would not see a paradise earth and that knowledge proved too much for him.
My point to him, and to you, is your life is still ahead of you. Don't get me wrong, I'd love to be 25 again. But I'm not. I'm 48, recently divorced and looking at starting over again. But looking back with regret is not productive. It doesn't help you.
I submit that you have the power and ability to make your life whatever you want. There's no time limit to this thing. You can start whenever you want, take it as far as you want and make it whatever you want.
For whatever reason, this life is full of problems and pain. I don't know if there is anything after this life. Maybe there is, maybe there isn't. One day we'll all find out. Until then, my feeling is that I'm going to deal with what is, rather than that I would like to be.
I don't think you've wasted anything. You've had an experience. Learn from it, use it, take what you need from it in order to grow and improve yourself.
Chris