We've all done some stupid things throughout our lives.
These stupid things have hurt others, and in retrospect we can only feel guilty for having done so.
But I say, don't feel guilty.
**** happens. Move on.

We can't fix what's done.
As far as I know time machines haven't been invented yet
so stop worrying about what you've done.
Instead learn from that mistake.
Let it turn you into a better and improved you.

We live in the now, as much as we'd like to go back.
Enjoy the moment.
Learn from the past.
Envision your future.
After all, the only thing that matters about our past, is where it takes us.