Yes, with fibromyalgia the pain, especially in the early stage of the disease can be very hit and miss. You may feel like you've described for several days, and think it must be the flu because suddenly you'll feel "normal" again. However, at least in my experience, when I thought I was back to normal, I'd push myself to do all the things I was accustomed to doing in a day, and that would put me right back into another flare up. So keep that in mind, listen to your body and don't over do it. It is good that you are keeping a log of your symptoms, that will help when you visit your doctor. Keep pushing your doctor for a diagnosis, if you don't get the results you believe you should, get another doctor. One thing that I've come to realize, YOU have to take control of your health and not expect that the doctors will do it for you! Take care and keep us posted.