Am I over reacting about this?

[Casey]

So i met a girl (we had a lot of mutual friends) 2 weeks before September. She goes to UBC so for the last month we only talked on facebook.

i liked her and i talked to a mutual friend about it, and she told the girl i like what i said. we basically had an awkward convo after that, I asked her out and she said she didn't feel she knew me enough and said "until i get to know you better, its a no for know". I asked her if she could keep it from the rest of the group because I didn't want things to be weird, she promised she wouldn't say anything

last night i found out from someone that she talked with a bunch of mutual friends over skype, and told them everything.

Even though she said no, we had decided to stay friends and I still kind of liked her but now I just hate her. she couldn't keep one little secret for me even though it wasn't a big deal to anyone other than me. She then lied about not saying anything when I asked her.

am i over reacting here? the way i see it, there is no way i'll ever want to date her after this, not sure if i even want to be her friend. as far as the other friends who knew and didnt say anything even though we've hung out a bunch of times since then, what should I say/do?