A girl had a crush on me now this?

So there was a girl who had a crush on me in my school on same grade 5...i dont know she likes me... but one day she told me tht she likes me and ask for me for be my gf i said her yes.....we were been in relation for 2 month b but we only meet on school i dont have her number neither does she so the only we we communicate to each other was letter nothing else right after 2 month she left the school and i dont know her number or anything else to contact her years passes after three year (now)/present) she contacred me through fb...we were talking first time on internet she ask me how was i and bla bla bla then she asked me tht i have a gf i said no then i ask her tht do u have bf she said yes i fell sad then days passes she daily msgs me she told her bf tht i was her crush her bf didnt like it and told her not to talk to me but she still does.... during chats she keeps reminding me tht she had a crush on me and she used to like me alot then i feel very happy but after few minutes she said tht i dont have crush on you now then i feel sad after 1 one day she asked me tht can she said me "i love you as a friend" i said yes why not then she said i love you then again i feel very happy at tht moment i was thinking tht she maybe again wants to be in a relation with me but after few minutes she said tht he likes her bf then i once again feel sad after 1 day she send me a picture of a girl and a boy kissing each other and said tht i used to think of you like this picture i was again feeling v.happy then she again said tht i dont think of anyone like this now not even me not even her bf i again feel sad i still like her...so one day she asked me tht i still like her i said leave it tht doesnt mattet then she strted pleasing me aand asked me again and again then i said yes i still like you then she said really i said yeah then she said tht im so so so sorry i cant do anything for you i feel very sad then ....then again she keep doing tht flirty thing i mean she is really giving me mixed signal sometimes i feel very happ sometimes i feel very sad then now i was talking to her then she said tht i will talk to you later coz im talking to my bf i said ok i dont knoy why she is doing this... should i ask her to decide whether she wants to be in relation with me or i ask her to leave coz sometimes i feel very very sad ?