Would you trust a friend after this?

Heck yes you deserve an explanation you just have to buck up and demand one from her. You certainly deserve it, and i dont mean to judge her as i dont know her and all, but she doesnt seem like a good friend at all. I'm wondering why you even hang out with her. A friend is someone who cares, not someone who would rip on ya if your grandmother dies. (sorry about that by the way). As much as it may hurt to think about or consider i think you should get her story about acting like she did and then flat out leave her.