Upping zoloft?

I'm not sure where to post this. I'm 38 weeks today and was prescribed zoloft 25 MG a month ago for anxiety. I've noticed a huge change and it was great, but this last week I've noticed my anxiety is creeping back in and some of my irritability. How do I know if I need to up it? Could it just be me getting closer to delivery or should I consider upping it to 50? I have an appointment today and I keep going back and forth. I'm almost afraid to take too much if that makes sense. I don't want to be a zombie and I don't want to jack things up right before my baby is born. Any advice?