You must stop COMPLETELY defending against their attacks or saying mean things back. If that means you have to walk out of the room, then do so. You be the hero in the family and just tell them that you are not going to get dragged into negative fights with them.
You have aspirations in life, or at least I hope you do. And every single day, working to achieve your aspirations is like pulling a big wagon up a mountain by only a big rope slung over your shoulder. The people in your life are either going to help and support you pulling your wagon, or they are just going to sit in your wagon as extra weight and burden with their feet up. That doesn't mean that you can't be loving and generous with them, but it does mean that you have to walk away, when they are being mean-spirited. If you must say something back, just say, "thank-you for sharing that." Doesn't mean that you agree or disagree, it only means that you heard what they said.
All that negative hatred that they project onto you is not about you! It's negativity that arises in their minds. If their criticism of you is not delivered in a calm, helpful, and loving spirit that actually helps you be a better person, then ignore it. If their criticism is delivered in an angry yell, bad name-calling, or some kind of diminishing put-down, then it's not about you. It's about them dragging your self-esteem into the ditch. God lives within you as you. You are a potential buddha. See the anger and hatred in others as ignorance. Their opinions of you are just that -- OPINIONS. Concepts in their mind.