Girl is Blackmailing

Hi, Few Months Back I met a girl on facebook and the we started talking daily day and night.We started liking each other,then we decided to meet.So one day we met for some time.But i notice a very strange behavior on her.She was touching me at every moment and then she asked for a kiss.I dont know why but i agreed and we kissed each other.Then after few minutes i told her to lets go back to home,But she refused completely and said i want to spend more time with you.In the mean while every time she want me to kiss and hold her.Her behavior was completely weird so i asked her forcefully that lets go back to home now as it is already late.Anyhow i manage to convince her to go back to home.After that day she continuously ask me to meet but honestly speaking,first meeting with her was so bad that i am not able to go and meet her now.I told her that the things you do is not good,But according to her if we are in relationship then these things are normal,But i told her that its still not good,Then with the time i realized that she dont love me and i cant make her every wish fulfill.So i told her that please stop all these else i will not able to continue,Then she started threatening me that if i leave this relationship.then i will spoil your and your family life.I will show each and every message of you to the police and will told the police that this guy has gone physical with me and now he is leaving me.I asked her and even request her not to do all these things but she is not ready to listen anything and whenever i told her that i am not happy with all these things an your behavior. She threaten me to destroy my and my family life. Please help me.i am really in trouble