Sister told friends i self harm?

[anonymous]

Im very close to me sister and love her very much. I also self harm a fair bit which she vaguely knows about. I have major trust issues (my phsyc told me) and my mum only knows by accident. My closest friends have no idea and it makes me feel sick to think of ANYONE knowing mainly because i dont trust anyone but myself but also because i am a very happy bubbly person and dont want people thinking of me any way but that. Anyway i was sitting on the couch next to my sister and her bf said to her on facebook, "is your sister ok now" my sis looked up at me and i pretended not to notice. A few months ago i found out she told her ex (after the break up) all about me and i almost threw up when i read it and saw how hugely shes exegerated like i was a sucidal maniac. So today i went on her laptop and discovered shes told her best friends and her boyfriend all about me and my cutting. She als said she only invites me along to with her when she goes places so i dont get kore depressed and just sit at home all day alone because i dont go out with friends often. Her friends added she was glad i couldnt go to the most recent thing i was invited to because i am extreemly akward (i didnt think this was true ad i am very confident and always talk to people etc) and my sister agreed saying she was happy i missed. I love my sister but im finding it really hard to face her knowing all shes told everyone. I have not mentioned anything to her but im so upset. What should i do?