Here's the deal OP. You have extremely limited amounts of energy. While you focus on the past, your present and future suffer for it.
This is what has worked for me so far, basically everything I do in terms of thinking about life I do it with my future self in mind. My past self doesn't exist anymore and never will again. My future self however has vasts amounts of potential so that's where I try to allocate my resources to.
You see how your past self royally fucked you over and now you have to deal with that shit? If you don't change your present, you're gonna do exactly that same shit to your future self. Except that at a certain point, your future self won't be able to do anything about it.
Rise to the challenge and be the first in a long line of "you" and set the building blocks that those future "you" can work with. Don't take the cowards way out and leave it for the next guy to deal with.