I was on Buspar and Xanax when I got pregnant with DS. Obviously, I had to stop taking both. (I was also on a string of other medication, both sleep and antidepressants that I was weaned off of) So, I understand the anxiety during pregnancy, and the difficult position that you're in.
If you don't want to be put on medication that is considered safe in pregnancy, then my advice to you is to meeting weekly with a therapist to voice your anxieties out in the open, with a professional. Additionally, the whole "mind, body and soul" really helped me with DS. Perhaps pregnancy yoga? Meditation?
Also, exercise is a great way to get natural endorphines flowing. It doesn't have to be strenuous, and you can do it in the comfort of your own home if you don't have a gym membership.
I urge you to speak with a medical professional about the boat loads of possibilities to address your anxiety without the use of medication.