Luna stared helplessly, her heart wracked with despair as the weight of hundreds of dreams tightened on her horn. How could she forgive herself when the past was an unchangeable testament to her failure? Her thoughts twisted in a spiral of self-recrimination.

Her mistakes loomed large, a shadow she could never outrun.

-

Basically the canon:
M6: So, Luna, if the big evil smoke monster feeds off you feeling bad about what your trangressions as a villian, which is all in the past by the way in case you don't know, you just gotta stop feeling bad for what you did! Because we already forgave you!
Luna: Oh goodness gracious, why didn’t I think about that! Okay!

Screw the canon.

Screw cartoon logic. Author decides to deviate from the canon.

This is what really happened.