Hi D.,
I have no experience with Pristiq, but am sadly very familiar with anxiety/panic disorder. I have just one child, and went off of Welbutrin and Clonazepam as soon as I suspected pregnancy...all I can tell you is that the pregnancy hormones seemed to compensate, and I was OK for the duration of the pregnancy without meds. Afterwards, however, I experienced much worse anxiety than I had ever had before and had to get into therapy and onto meds. right away.
Ultimately, what's worked best for me, and this is certainly safe for you to do now...has been neurofeedback. It is wonderfully relaxing, and "teaches" your brain how to respond to anxiety differently. I'd be happy to tell you more if you're curious.
Good luck, and do take care of yourself. Anxiety can be crippling; I know. You have my sympathies.