<human>: My best friend and I have been inseparable since grade three. She moved away, and our relationship didn't suffer. When she eventually moved back (three years ago) her family ran in to serious financial problems. In order to be able to afford a home, her family was going to have to move to Florida. She'd been moved around countless times before, and was devastated about leaving the state. My family considers her to be one of our own, and we invited her to move in. She did. I am a very busy person, with rehearsals and extra-curricular activities going on all the time. I'm also quite temperamental. When my friend moved in, she only hung out with my sister. She would never show interest in spending time with me, and in the 6 months she lived with us, we never once slept in the same room. Now I see he at school and we are still friends, but she's always around my sister. She invites her over all the time and they have become what she and I used to be. I can't stand it, but I don't have the heart to tell her. I think it's unreasonable for me to ask her to sever their friendship because I know my sister is very close to her and she would be upset. It's gotten to the point where my friend's family knows my sister better than they know me. What should I do, am I wrong  for absolutely hating this?

Can you condense the text into a few key points?
<bot>: I don't like my sister, and she's now closer to my best friend than I am. How can I help this?