Girl blackmailing to me

Hello sir/mam.. i cannot reveal my name but i m in a very serious trouble please give me some favourable suggestion so that i can get out of it. I met a girl 5 months before through our mutual friend. i got her number from that girl itself. From that day we meet outside in all our free time. One day my fingers got injured by a ceiling fan, when she saw that she hugged me and expressed sympathy. i felt good so accidentally i said i love you but didn't mean that after then she walked away. Next day i went to her and apologies that i wasn't mean that but she cried and said she loves me. i pity on her and continue the relationship even we had sex in 3 or 4th meeting. before that i have cleared everything that i could not marry you because she was st category and i m brahmin boy my parents couldn't allow. she hadn't any problem with that and started making love all the time we met. During this period i found her being possessive and torturing me by saying if you will cheat me i will go for commit suicide.. I fed up of her behaviour changing day by day. she used to cry all the time and blackmail me to not leave her or else she commit suicide. Just because of fearness i had to be with her. After this 5 months i realise we cannot stretch our relation far longer now. so i change my number and place where i lived. This is my turning point where she started my life to became hell. she continue call to my friends who were in my facebook. Even not stop here she find out people of my same name title(surname) and talk to every my relatives in social media and got my father names, number and address too. when she got my father number one day she called her and said that she is pregnant. not only my father but all my relative to destroy my image in front of everyone. she came my home to threaten my parents, she said that i was promised her to marry her but i never did so. she is making my life so hell what to do i don't know.. she still searching me. is there any law for girls blackmailing. how can i get rid of her?