How do i can stop thinking about a former friend?

I used to be friends with 2 guys and we always did everything together. But all that changed when i started suffering from a rare mental illness called Social Anxiety and overnight i became an introvert. The 2 guys i was friends with began making disparaging remarks about me behind my back and always made it quite clear that i was not wanted at their houses though at the time i did not get the message and i came across as being sad and desperate. 10 years later despite not being friends anymore i still think about those remarks they made about me and i often say to myself that i should try and move on, saying to myself that that's all ancient history but for some reason i just can't forget about them. Any ideas as to how i should stop feeling guilty about the past and look forward?