Don't hate yourself, you have very good reasons not to trust her.
She's not a particularly good person to be around if she's running off sharing your private discussions.
I do think there are people out there who need to be with others they can boss around. They're the same kind of people who beg you to come out to a club with them and then leave you sitting by yourself all night long. The kind of people who plan trips based around their own wants and needs and not those of the company they keep.
Friendship of anykind is a two-way street, it's all about sharing and discovering together - it shouldn't always be about one person. That's probably the reason you've not felt motivated to get in touch with her - I don't blame you at all.