Chastity, I just learned something new today, thanks to you! I just got done telling someone that the joint pain that I feel is due to fibro because I get it and then it disappears. (Fibromyalgia affects muscles, tendons, and ligaments so it can feel like your joint is hurting but it's really muscular.) I didn't think arthritis ever disappeared since it damages your joints. But then I just checked it out and there is something called reactive arthritis that is auto-immune, of course! So this may be playing into it, too. Here is a link from the Mayo Clinic about it.
http://www.mayoclinic.org/medical-edge-newspaper-2007/oct-29.html
I have heard that fibromyalgia is not an auto immune problem but I sure think it is. I have fibro, Crohn's, diabetes, and auto immune inner ear disease. Everything I have is auto immune. Fun, huh?
There is a definite difference between fibromyalgia and arthritis, though. Go to the Fibro 101 thread. It is the second thread from the top of the forum. There are links in there with good information about fibro. There is a link to symptoms of fibromyalgia. You may see many things that you are experiencing there.
If, after having your baby, you are still experiencing problems, be sure to ask questions. We may be able to help you. You do have to be careful what you take, since you are pregnant so I won't go into that now. But, you may find hot showers and moist heat beneficial. I have a rice bag that I heat in the microwave that gives off moist heat for nearly a half an hour. It does feel good. Also, on that Fibro 101 thread, there is a link to gentle stretching exercises that will help you. Walking is great for you too. You do need to keep moving to keep the muscles flexible.
I hope some of this helps you. It's hard to explain since the doctors don't even know what causes fibro. Some doctors, who live in caves, don't believe it exists! Let them crawl in my body sometime! 
Sherrine