A girl is blackmailing me to marry her

Actually we were friends earlier and and after a long time we started to like each other and she proposed me many a times i rejected saying i cant be in a relation because of my family and many other reasons.. She always seduced me me over text n phone one day i really fell into the trap n replied her.. After some days she asked me for sex stating she has no intentions of marrying me in case i dnt want to.. Bt i rejected one day she came to my room and stayed there for a night because she came from a lot of far distanne n didnt find any good lodges or something..she seduced me that night and i fell for her and we had sex bt i clearly mentioned her that am nt gonna marry her before the intercourse only ..n luckily she s not pregnant Now she says that she has been to a doctor for a check up n doctory found that her overies hav been expanded nw she is threatning me to marry her or else she is gonna tell my parents n file a police case am so tensed this would end my life am just a graduate i hav family responsibiloties.. What would be appropriate to do in this situation please help me i even hav proof of our conversations over whatsapp stating my clear intentions of nt marrying her n i hav told her that before the intercourse itself.. Please do help me in this regard..