In four years, is this the first time she has said something like this? Or was she echoing what you were expressing to her, that you didn't know why you were there? If, in four years, this is the first time either of you have felt like this, that's pretty remarkable, but if it's somewhat of a pattern, I'd be worried.

That's not to say that a comment like that isn't incredibly painful to hear, especially if you've just begun to trust her. Maybe try to think through if you gave off those signals first, or if it's been an ongoing theme where you don't feel you're getting anywhere. This can be a good discussion if you take it there.