As people said above, there are different kinds of depression and they occur in varying degrees. Dysthymia is a less severe kind of depression, for example. Just because you can maintain your daily life doesn't mean your fine if you don't feel fine.

You said she doesn't see you as having a "psychiatric" diagnosis, does that just mean she doesn't think you need medication, or that she thinks there's nothing wrong with you? If she thinks there's nothing wrong with you, what is she treating you for?