My mental health is ruined

The bullying that went down my last year of highschool because I was trying to leave on good terms has ruined me. They said they were upset that i get to be happy when I'm one of the worst people they met and I don't know if they're right. I made one bad decision and some iffy ones in my friend group and I can't help but feel like they're right. I've totally given up on my dream because the world is not forgiving and I know if my bullies got their chance my life would be ruined.