My heart goes out to all of you! I have had two children, and both pregnancies triggered GAD that was unbelievable.
With my first pregnancy, especially during the third trimester, I was so panicky and having so much anxiety, and I really didn't recognize what was going on. Even though I have always had GAD, it was never to the extreme it was during pregnancy or postpartum. About a week after delivering the baby, I got on anti-anxiety meds, and I'm so thankful that I did. I have since gone off of them (when I got pregnant with my second son), but do consider going back on occasionally.
With the second pregnancy and postpartum, I knew what to expect, so it was much easier to manage.
After you have the baby, if you still feel very anxious, don't hesitate to get the help you need ASAP! The final weeks of pregnancy and postpartum can be the most stressful (especially when you don't get enough sleep), so be sure to take care of yourself. Get lots of help from family and friends (and husbands) if you are able to and take breaks for yourself so you get rest and time to try to de-stress (a hot bath, a dinner or lunch out with girlfriends, a yoga class, anything to help you unwind and relax a little).
Best wishes to you and your new little ones.