I don't think your therapist was making a universal declaration but a statement about you. Assessing a level of functioning is always a part of DSM V diagnosing, so obviously being high functioning is relevant. I don't think it's as simple as you may have heard, but what I hear is a therapist resisting the urge to pathologize your struggles and instead of focusing on your strengths, which is your functioning. This is one way to start to build someone up. Maybe you don't need it but what difference does a disorder/label make in terms of what you have to work on?

You have the same things that cause you pain no matter what the diagnostic label is. And if your therapist says something that strikes you as wrong or you wonder about its validity, why not ask her (not saying it's wrong to post here)?