That sounds really frustrating. It's hard to do and you probably know this already but it will help to tell her how frustrating it was for you and that your mad at her. It might have been out of her control to let you know sooner or she just didn't remember how much planning it takes on your end to make the trip but either way it would still be useful to talk about. I have the feeling if you don't go see her now and put it off it will be hard to go in the future. At least it would be for me anyway.