Hi and welcome.
To make things clear you have RA and FM. There are no blood tests to test for FM yet but from the sounds of it, it may be coming within the next few years.
A great book, which I call the "FM Bible" is Fibromyalgia and Chronic Myofascial Pain: A Survival Manual by Devin J. Starlanyl and Mary Ellen Copeland does a great job in explaining the illness and breaks things down by chapter for you. It is in its second edition finally and I am sure there are newer things in that one than I have in my first edition. I haven't seen it yet. The book is available in any bookstore or at amazon.com or barnes and noble (bn.com).
If you have any questions, feel free to ask. It is the only way to find out anything.