Hi Nick. Jocelyn is right. FMS is a dumping ground diagnosis for "you hurt and we don't know why," and you need to demand a very thorough workup to see what is wrong. You might need to repeat tests, or research the "right" tests. Viral testing might require several different types of test at different times. Also, the laboratories often do not keep specimens at the proper temperature, or they botch the testing, so you get false negatives. Don't assume one test is correct.
FMS is a "syndrome," meaning it's a collection of symptoms - you may have some or all - but it's not a single "disease," per se. The drug companies are advertising it in a way that it seems so, but in my opinion, this is an attempt to sell Cymbalta and Lyrica, etc. Are you taking any drugs? Because often, weird symptoms are from drugs like the antidepressants prescribed for FMS - so you might want to check with a good PhD pharmacist, and go over all the drugs you are taking (ALL of them, OTC and supplements too) to check for interactions and side effects. Also, sometimes people are reacting to the dyes or fillers in generic drugs.
Fibromyalgia can be a misdiagnosis in certain cases; e.g., a person might have an autoimmune disease like M.S., or an infection like Lyme Disease (hard to diagnose and requires repeated and accurate testing), or some kind of hepatitis or herpes infection (there are 8 different strains of herpes virus, maybe more). You could also have triggered something like celiac disease (the severe form of gluten intolerance). Most doctors know very little about this. Check out the Celiac Sprue Foundation. You can have celiac without GI symptoms - something most doctors don't know. There is a blood test for it.
You should request a test for food allergies, including one for delayed food allergies while you are still eating your regular diet. LabCorp offers a test for over 90 food allergies. Celiac disease can cause all kinds of problems, including neurological, musculoskeletal pain, etc. My new rheumy tells me a lot of his patients do better on a gluten free diet. It worked wonders for me - but I figured it out from my research. Most doctors are completely ignorant about it. You can get an e-book online called Dangerous Grains that links gluten to a host of diseases, many of them linked with FMS. The gluten free diet cured my "fibro" muscle pain. I also got lidocaine injections into the big painful muscle knots and they, along with deep massage, broke up the knots. But I still have the exhaustion. Some of the symptoms of celiac disease match yours - canker sores, bloating, disturbed sleep, neurological problems, lowered immune system so you catch infections, very painful joints - and also depression, if you have that? In fact, some of the symptoms also match up with side effects of Cymbalta - you don't say if you are taking that.
A very good supplement to help with sleep is melatonin, sublingual works the best I believe. It is the hormone your brain makes for sleep. I now rely on it, and only occasionally take 3-5 mg of Ambien with it. Some people go to sleep with 3 mg. Melatonin I need 10-12 mg to get sleepy, and if I wake up at night, I take another 2.5 mg sublingual tablet. Read up on this, talk to your doctor or pharmacist before taking it. There are some sources that say it is risky because it's a hormone. Educate yourself and decide what you want to try. It's also good to keep a notebook of what your symptoms are, what you ate or what you did, and whatever supplements or treatments you tried. Over time your patterns will become clear and you will know what makes you feel better.
Best thing we can all do is educate ourselves. A couple good books are "Fibromyalgia for Dummies" and "Fatigued to Fantastic" by Dr. Jacob Teitelbaum who has FMS himself. You can google him - I believe he will consult with patients online. There are a number of fibromyalgia doctors online. Some feel that FMS is linked with Lyme Disease. Some will work with you on viral testing. Some believe FMS can be treated with magnesium. It's up to YOU to educate yourself and decide what matches up to your symptoms - many regular doctors just don't have time to carefully assess all your symptoms and diagnose you. It's easier if you do the research, print off what you think applies and take it with you to the doctor.
All of us have different complexes of the symptoms of FMS, most of us have a very hard time finding a sympathetic and knowledgeable doctor. I think we are frustrating because we require a lot of time up front to get a good diagnosis. Doctors are pressed for time. It's easier for them to hand you a prescription for an antidepressant. Some people find some relief with them, but a lot of people have a hard time with them - and they are highly addictive, have side effects, and are almost impossible to quit once you start. So before you start any drugs, read the forums and do your own research, avoiding the drug company sites. Two good sites to research drugs on are peoplespharmacy (dot) com and drugs (dot) com.
And let us know how are progressing. It sounds like are better than you were! Good luck to you.