My sister is trying to control my life.?

I am 14 years old. my sister found my journal and read that i had sex with my ex. and then she made me a contract and rules to follow or else she is going to tell my mother...she said i couldnt date my boyfriend anymore, and i couldnt have any boyfriends. said i have to have a tutor for school, do daily chores, and make my boyfriend move out of my house..... my boyfriend and i have been together 4 months... he has lived with me since we started going out because his parents are both drugies. after my sister told me i couldnt be with my boyfriend anymore i told him we either had to break up or hide the fact that we are togetther... we both did not want to break up att all. so we kept it secret... he eventually moved back in with me.. and told my sister we were just friends... one night he was at his friends house and his friend left and told him he was going over to some guys house to get alcohol.. he came to my houise instead and tryd to have sex with me... i kept saying noo but he kept trying... to put his hands down my pants and used force to put my hands down his.... i flipped out.. and cried all night.. bcuz he had kissd me... when he left i called my boyfriend immditaly but he was sleeping... the next day i told him everything that happend and he wanted to kill his "bestfriend"... i told my mom tht night and she said he could go to jail for attempt of rape... and asked me if i have had sex yet and i told her yes.... but i messed up and told her a different ex then my sister knows about.... sop my sister know about one of my tattoos, and me having sex with my ex *aj. and my mom knows about a different tattoo of mine , and me having sex with an ex * Ronnie....my sister just called me and told me she knows that me and my boyfriend are still together and that we are going to go through the rules i broke and come up with a consequence,,..... she told me i better break up with him..... so now if she tells my mom...they will be pissd to know i have had sex with two of my ex's.....and i will die..... i messed up bigg time/...... how do i tell my sister that she cant control my life anymore....? and that she is basically blackmailing me...? Just please help. im tired of hiding the fact that me and my boyfriend are dating.......Helpp.. please im begging