J.,
It definitely sounds like ppd. I didn't have the exact symptoms, but like you I had never had it with my other pregnancies, am normally upbeat/positive, etc. and could still "reason" with myself--but it didn't change the pain I felt.
I called it my mental migraine--feelings of anxiety and all that would come and go, though I did nothing differently. Eventually it stayed and I sought help (I couldn't even cook a meal or pack a lunch--showering, dressing, etc. made me anxious which I NEVER experienced anything of the sort before--I was never an anxious person at all).
Like you, I had no desire to go on medication. When the symptoms wouldn't go away, there was nothing I could do to "talk myself out of it." I got out, went for walks, kept myself busy, reached out, had tons of family/spouse support but that wasn't enough. I finally went on Paxil and for me, that made all the difference.
That said, there were some sort of "withdrawal symptoms" going off of Paxil--but I went cold turkey after 2 years instead of tapering off. A year later (3 years from the depression) I feel like myself without medication--happy and healthy. It wasn't quick, easy, and painless, but I am a much better person from what I experienced and can reach out to others in ways I never could before.
I hope I didn't depress you more with the part about the medication, but I know I would have wanted someone to tell me that it might not be easy, but that it was doable. In hindsight I would still take the medicine all over again, without a single doubt. It was part of the healing process, but like stitches/packing, etc. with a physical wound, it wasn't painless to remove (hope that makes sense).
Take care of yourself--I'm so glad you've got an appointment. You sound like a strong woman and you'll get through this. . .definitely for yourself, and especially for your children and spouse b/c they feel the effects as well.
J.