I'm deeply ashamed to admit that if anyone, anyone, in my family had done what I did and begun to "Apostatise"... I'd have shunned them into an almost literal non-existence.
Is it just me that was a douche? (I'm improving, slowly.)
Nope, many of us are in the same boat - I've been a shunner as well as a shunnee. I've shunned a parent and been shunned by a parent. I know both sides of the deal.
Look at it this way - we were all in ... until we weren't. That's all there is to it.
Look on the positive side: did you bring someone else into the 'truth'? If not, then be happy at that.
If you did bring someone in ... well, at least it wasn't 2. If you brought 2 in then at least it wasn't 3 ... and so on.
We can all regret the past but it's pointless - you're allowed to forgive yourself. If you feel bad then you can't be such a bad person.