Does not sound like you're doing anything wrong from what I've read. Like Rhapsody said maybe she's being influenced by her boyfriend. You have to understand that maybe she does not have the same feelings for you that you have for her.
Either that or she's grown lethargic of long distant relationships since they take effort. I dunno it's hard to say.
But as far as you're concerned you played your cards straight.
Have you considered going to see her instead?