I usually have the same problem when the angle of the sunlight begins to change in late August. This year, not so much because I'm well-medicated and stable, but I had issues in the past, pretty much every year.

I also have SAD, though I've never been given an official diagnosis. All my issues seem to fall under the big ol' bipolar umbrella. My dawn simulator made a huge difference last winter; my pdoc recommended that over a light box because I'm apt to become manic for any reason or no reason. Still, I'm lucky to get through an entire late fall/winter without a depressive episode, so I very much feel your pain!