I did something I can never take back
Was this something that happened in the past?
Yes, it was an event that I can never take back and it really hurt my entire family.
The fact that you're acknowledging a mistake is an important first step towards making up for it.  I hope you find success at that!
I feel guilty but I'm working on it.
It's normal to feel guilty if you've done something you regret. I think you're well on your way to righting the past wrong.