When I found out I was pregnant I was taking Effexor XR and Xanax. I'm sad to report to you that I have made the decision to come off of them. Xanax causes birth defects and Effexor has a low risk but like you I was terrified to take it for fear of causing a defect. I wasn't trying to get pregnant but once I got used to the idea I wanted to do what was best... or what I believed to be best. I have suffered from anxiety and depression since I was very young and quitting those meds in the first trimester was one of the hardest things I have ever had to do because of the horrible withdrawal symptoms on top of early pregnancy symptoms. I still have horrible anxiety but I'm just trying to cope as best I can. What it comes down to I guess is what will make you feel like you did the right thing. This is corny but the answer comes from within, but keep in mind... without a healthy you, a healthy baby is not very likely.
I hope this helps you... or at least gives you something to think about. I'm in my second trimester now and everything seems to be doing fine. I even seem to be doing okay. I'm sure you will make the right choice.