My sister has been mean to me my whole life.. We're not really close at all, and when I try to bond with her, she just uses me for a short period of time, and then the next day continues to tease me. I understand what your going through. I ussually just try to ignore it, and try not to insult her back. That's what she's looking for, to make you angry and pick a fight. I've realized that she's not really a sister to me, more just like a roomate that'll be living with me for only 2 more years. It's sad, but that's just how it is for me. Try to get friend to replace that sister bond you've never had. It works, but just make sure you choose a good person. My sister has made me so depressed that I tried overdosing a couple months ago. Not worth it.. Inbox me if you need anything. Hope this helped.