I respectfully disagree with Mr_Luxo, and to be honest, their mindset reminds me of those people (who were often abused themselves) who have the opinion that, "Everyone has a hard life, get over it, you're not special and the abuse you suffered wasn't that bad." I can't stand it when people make judgements like that about someone else's childhood. We weren't there, but OP was, and that's what matters. I would never tell someone that what they experienced "wasn't that bad", especially when they seem to be having such a hard time with the consequences and fallout.

Adding to that, u/Emotional-Ear-2945, I don't think that what your parents did was normal, nor was it ok, even if they were trying to protect your sister. And it's NOT your fault! It's crushing and so sad when parents manage to destroy the relationships that their children have with each other.

I'm sorry that you're going through this, and I'm glad that you've decided to talk with your sister. I hope it goes well.