I was on Lexapro 10 mg throughout both of my pregnancies. I also breast fed both times. Fortunately my children are quite healthy. My anxiety increased during pregnancy which is completely normal. I would try to just work through it and not increase the dose if I were you. Try to focus on all the fun and excitement coming your way and hopefully you will settle down soon.
I have panic disorder, and was on 37.5mg of Effexor all though my pregnancy. I spoke with a place called Mother Risk at the big children's hosiptal in the city, and they provided me with results of various studies on my specific medication, and based on the studies, there were no long terms effects to children. My son is now 3.5 years, and we have had no issues with any kinds of delay. Anxiety from panic disorder can affect the child, so sometimes it is worth the slight risk to continue the medication through the pregnancy. Have you discussed with your doctor?
Keep in mind that no medication is believed safe when pregnant, so if you are going to risk it, and I believe Zoloft is considered the safest one but not safe, then I'd think a higher dose is still worse for your child. So I wouldn't do that. But hormones affect women who don't have anxiety problems, and pregnancy can throw hormones into daffiness. That's adding stress to a problem you already have, but it's normal stress, not illness stress. I'd try to just stick it out, if you're able. Good luck.