We have all done things that we regret.
Sometimes our pride gets in the way of acknowledging the hurtful things we have said and done, maybe many years ago and the people /person we hurt is no longer around to say sorry to.
There is someone we can say a big, deep, heartfelt sorry to. Someone who is 'omniscient'. A lovely word, only God is omniscient. (see explanation in link at bottom of page).
He hears our cries for help, our cries for forgiveness, our cries for comfort and peace.
Call out to Him in your mind with heartfelt sincerity, perhaps when you are settling down for a nights rest, although any time will do.
There is nothing to lose and everything to gain.
Why carry the burden of your past any longer.
Ask God to forgive you for everything that you have done against His will in the past.
Why not give it a try tonight?
It's your life.