I'm so sorry for the hurt and confusion this must cause you. You didn't mention whether you have a relationship with your siblings. You've tried and she is not receptive. Would it be possible to sit and have a discussion with her about this? Would she be willing to do that? If she's not receptive it might be time to see a therapist to help you process your feelings. You can also build or create your own "family"....close friends with your best interests at heart. I'm not saying cut her off. I'm just saying build your life and she'll come around or she won't but you will have built your life.