Five years ago I think I emotionally destroyed someone and it has ruined my life.
Do you really think destroying someone is the reason for your miserable life?
Yes, otherwise I wouldn't have to hide my shame.
Tearing apart someone else's life can create shame because it's wrong to hurt people. Give yourself forgiveness and learn from your mistake.
I didn't know I was doing it. Whatever it's too late now.
You could still apologize to that person and try making their life better, and in a way you would be making your life better too. You should never hurt someone emotionally and then leave them to their own sadness.