Once you have truly felt the pain of your past and accepted the feeling that makes you think you can't hold on anymore you can then feel that tiny shred of strength to pick yourself and move on. Don't revisit it, don't use it as an excuse. Just move on.
No matter what happens, no matter how far you seem to be away from where you want to be, never stop believing that you will somehow make it. Have an unrelenting belief that things will work out, that the long road has a purpose, that the things that you desire may not happen today, but they will happen. Continue to persist and persevere.