Let the past go. You don't have to be stuck in the past for you to have a hard time letting go, either. Regrets, unresolved problems, and all of the what-ifs that could spring up are all from the past. And when you know you are not alone in this, you gain a sense of strength to tackle the problem. Your mind would be focused on the issue at hand, not your lack of capability to solve it.
Acceptance will make all the difference. Some things shed and no longer serve a purpose. Some things are just out of your control. Learn and move on. It's better to heal and get prepared for the future. Instead release worries and aniexties, spend time with love ones and look at your problems from a detached and structured way and chop them down little by little.