Well, do you have to have her as your referee?
As for whether you can do anything about it, certainly. If you can find someone else to act as your referee then you can look into applying as an independent candidate and not go through your school at all.
Really, though, I think she's just trying to scare you into buckling down and working. I suspect that as long as she sees you working hard, she'll be happy. So make her happy
-- A.