I'm not sure where to start with this....

I have an older sister, who I have always had problems with, off and on, growing up. For the most part, she tormented me throughout the years, she was really pretty and popular in school, and I was not the most attractive, and not the most popular, i've always marched to the beat of my own drum. Anyway, because of this, she treated me poorly, and we didn't have much of a relationship. She was diagnosed with bipolar disorder, and gained 200 plus pounds, from a combination of her medication and her not wanting to do anything anymore.

When we became adults, she moved nearby, and I started coming over to her apartment, and calling her, and helping her with her emotional problems, and anything else she asked of me. I never asked for anything in return, as I have found out that asking her for anything makes her angry with me, and I don't usually help others with the thought of getting something in return.
Anyway, she is on a fixed income, of about 700 dollars a month, and recieves about 150 dollars in food stamps a month, just for her.
I am unemployed, living in a small town, where there are no job openings at the moment....i've been looking for months...so money is very tight for me, yet, she ended up gambling most of her money away each month for several months now, and I have helped her with monetary issues when I can.

She disappared for awhile, (I am assuming upstate to a casino), and I heard she was back in town, so I went to her apartment building, to see if she was okay and if she needed anything. Plus, she's my sister, and I wanted to see her. Well, I buzzed her room, and after 15 minutes of standing in the main doors waiting for her, and elderly lady came to the door and told me that my sister did not want anything to do with me and I needed to leave.

I don't understand, my feelings are very hurt...I have not done anything to my knowlege to make her do such a hurtful thing....the last time I talked to her was about a month ago, when she called me from a casino and asked me to check her mail, and read it to her, which I did.

I don't know what to do about this, any suggestions? I feel really used.