i think dragonfly voices an important consideration in your deciding what to do about your current situation. Your boss needs to know that you will address quickly anything that may affect your work. She's given you time to do that, so you must meet her part-way.

If you trust you PCP to be a good doctor, ask whether s/he feels comfortable prescribing for depression. If the answer's yes, go with that. If 1 Dec comes & you're not better, or if PCP's not comfortable prescribing for depression, ask for a referral to a psychiatrist.

At least, that's what I'd do.

In the meantime...