Anthem, people that have substance abuse issues usually have regrets, and you can make it as simple or complicated as you choose. Regrets are just that, a regret. Something you wish you hadn't done. One thing is a guarantee, you can't un-ring that bell.
I can only share my experience, I had many regrets. Awful things I did twenty some odd years ago, I struggled terribly with the shame, guilt and embarrassment, But over time it faded (and what a relief that was) It also made me try even harder to redeem myself from such abhorrent behavior. Stay on the straight and narrow and those regrets will fade and you will feel so much better. Keep it going man.