Someone gave me this piece of advice and I think you might benefit from it: you need to mentally divorce your family (mom and sister especially). Make it an amicable divorce but a divorce nonetheless.

You don't need to tell them. In fact, don't. But just let things lie low for a while and think about how you will begin to renegotiate your relationship. (Not answering phone calls, texts, and emails overtime they send them to you is tremendously liberating.)

As a part of this divorce, think about them as you might your friend's mom or friend's sister--you want the best for them, you want them to be happy, but you do not need to bend over backwards to accommodate their requests or live according to their expectations. You are an adult and they have no control over you. After a period of not talking, reconnect. It will be awkward. But set up clear, healthy boundaries (after laying low for a while). If they begin to step over them, stop the interaction immediately or remind them of your boundaries that you set up with them. They are like Pavlov's dog and need to be retrained. This might mean walking out of the house, hanging up the phone, anything to stop the abuse but they will eventually begin to see that their tactics (screaming, passive or outright aggressiveness) are unacceptable.

Stop arguing. Stop trying to correct their misconceived, myopic opinions. It is no use. I know it's hard. But they will never listen and will just dig their heels in harder. And what they think or believe doesn't really matter. Just set up and maintain your boundaries and if not you will be fully within your rights to decide to what extent this relationship continues.

Best of luck.