How can I forget about the past and get red of my self-doubt and Ignore the bad reputation?

How can I forget about the past and get red of my self-doubt and Ignore the bad reputation I am currently having. I was slandered and bullied a lot and I am afraid I made some mistakes like calling bad names but only some times and i can't forget about the past and forget how people look at me... I also feel i have the right to be slandered and bullied...