Yep. It's happenning to me right now.
I found recently that shaking her confidence helped that. If the same thing is happening to you it's probably because you're not pressuring her (I call her once a week, never more than that), but she feels you're pursuing her (by the way you act).
So make her less confident. Break a date, or be silent in the last few minutes of a date. It worked for me...