J.B.
It could be SPD, or symphasis pubis dysfunction. It's common but not normal and can be treated with physical therapy or chiropractic during pregnancy. Basically, the pubic bone is made up of two halves and joins at the pubic symphasis joint. This joint is supposed to stretch a bit during pregnancy but sometimes it can stretch too far or fall out of alignment, causing tremendous pain and discomfort.
I developed public pain after the birth of my second child and was treated for SPD with physical therapy. It tuned out to be something different (oesteitis pubis, or inflammation of the public bone), which was treated with a course of anti-inflammatory drugs and it hasn't bothered me in subsequent pregnancies.
Search for SPD and see if the symptoms fit you, then call your doc and talk about it. He or she should be familiar with this and should be able to refer you to a PT or chiro. If not, then I would just seek out a chiropractor who deals with pregnant women and have him or her treat you for this. It could be that all you need is a simple alignment to begin to feel better.
Best wishes to you, and congrats on your pregnancy!