I know several people who have taken zoloft while pregnant without any problems. I know they sometimes give it to women that have a history of ppd. I also wouldn't worry about the ativan because your dr would have considered the risks to mom and baby. I too suffer from occasional panic attacks and I feel for you! I hope the meds are helping.
I have not been on either drug, but if you are really concerned, please contact your doctor. There is a reason this was prescribed to you. They should be taking into account the fact that you are pregnant and giving you something that will either not affect the baby or have very little affect on the baby. I know my sister in law was on zoloft while pregnant with my neice and everything turned out fine.