I'm done

It's amazing how good intentions can be blown way out of proportion and end up being the cause of major problems. I was trying to help and all I got was ridicule and being told it wasn't my place. I got mad and said some things I regret (which tends to happen from time to time) and I apologized for them and now we have gotten so off topic that apparently my apologies aren't good enough anymore. I can't exactly block this person out of my life, because it's my sister. I hate that we are fighting and I hate that I'm being blamed. I was honestly trying not to make this a big deal, but now it has come to such a head that we are only fighting about something that doesn't matter....Everytime I try to change the subject or apologize for something I've said or anything, it's always brought back. I've considered blocking her email and I've considered blocking her out of my life, but blood is thicker than water and we ARE sisters. I guess this has happened before, because we are both stubborn, but from the beginning I have told her that I don't want this to be a big deal, that I never wanted this to be a big deal. She keeps talking about it and keeps emailing me about it and it's getting really frustrating and I don't know what to do. I want to clear the air, but whenever I try to tell her where I'm at and what's going on, all I get is defensiveness and arguments. I just want to forget this whole thing happened and I want to go back to the way things were. I hate that I dread checking facebook, because she might have sent me another email and might be yelling at me or swearing at me again. I stress out about it, which isn't good because I'm pregnant. I wonder how I can fix things, but then again, everytime I try - it gets thrown back in my face....Not sure what to do...Just frustrated, tired and done with the whole thing.....I'm done.