Girl wants to kill me/ harm herself/put a rape charge on me

I come in contact with one girl, she is more into sex, as she told she like to sex with me, I had never sex before so I agreed. We had sex on multiple occasions now the thing is the girl always want to talk to me, track my every move. She want I should talk to her all the time where I go or where I'm now. Later I realized she started liking me now the thing is I started telling her it's of no use I don't fell the same way . When I refused her sex proposal, She started blackmailing me with the photos of us being together taken previously. Sending those photos to my relatives. She also says she will go to police for rape case. Can I file a FIR against her on grounds of defamation/ murder threat/ suicide threats/ blackmailing/. What do I do of police says that I will put this as complaint in his diary. In that case Do I need to put another complaint in front of magistrate . When Girl know that I have filed a complaint against her in police can she goes to her local police station and lodge rape case against me and make me arrested as we live in other localities. Is the girl be arrested on grounds that she is a threat to my life. please suggest me a better or best suitable way to deal the situation I'm in. What happens in filing complaint to police station and settlement in front of them. Can later the girl bring all these once again even after settlement.Thanks a lot for help.