My B.F.F.L Backstabbed Me!!!!!!

My best friend Haley she is like my sister! people mistake us 4 sisters but she promised that she wouldn't  tell anyone...... And there is this girl and her name is Taylor and Haley HATES!!! her but even though Haley PROMISED me she still went behind my back and told Taylor!!!!!!!! She promised me and now i just said why did you tell her? you promised me but you lied?! and now she is kinda mad at me and i said sorry but she hasn't emailed me back! IDK  what she is going to say.