What is she thinking she is doing?

I had this friend,Mandy, Whom i really loved. i have know her for almost 3 year. first when we met she looked familar. then when i told her my everything she told someone. then i was upset that i had to stay away from her for 2 month then she said she was sorry and i forgave her. then a year later. we dont talk much she txt me over the summer she said she missed me. then when we saw each other in school. we talked then i have some other group of friend then when i went to Mandy is party, she let me on hold. so the week after her party she backstabbed me again.i was so upset i think our friendship will go this way. on and off. so 1 month later she said she was sorry and i forgave her. then this summer she txt me and we talked and stuff. when i txt her most of the time she didnt answer. then when she was online she didnt talk to me she keep me on hold i was so worry about her i think she is playing with my heart.. she keep saying i luv u, i adore u, ure my bff. but she never talked to me