The only thing that calms my nerves is prayer. But I also try to be wise and help my physical body by taking a magnesium supplement called "Calm". I got it at Sprouts/ Henry's but should be sold at health food stores too. Also check out essential oils - doterra had one called serenity that my friends swear by. Not sure if safe for pregnancy, but other oils will be that can help. Good luck and praying for you!
I've been off meds for a few years now I've had very high anxiety. I've learned to cope with by talking myself out of it. If its really bad write everything down that is going through your mind that exact moment. Write until u feel you are at ease. Don't read it rip it up burn it do whatever will make u feel better. Hope this helps its helped me a lot also calming music and deep breaths I prefer jack johnson. Good luck!
Realize that if you can't do anything about it, such as its in the past, you have to let it go. If you can do something about it, ask yourself what's the worst that can happen and accept it and work from there. If you ask yourself "what if..." Answer your question.
If none of this is helpful, counseling is pretty helpful to discern your thinking patterns and work to correct them.