Hi Catbird!
I completely know how you feel. I have been suffering my fibromyalgia all my life and at 30 I have FINALLY been diagnosed. All the rest of the time people ignored me when I said I was in pain, told me I was a whiner, an attention seeker, so on and so forth. Often family and other loved ones would roll their eyes and say things like "oh here we go again" when I would complain about pain. Support is SO IMPORTANT though when you are dealing with this type of pain (made worse by stress!) and honestly, and this might seem harsh, you do not have the ENERGY to have anyone in your life who does not support you. What has changed my life is realizing this and shedding the dead weight by telling people in my life that (a) I AM VERY SICK and they must listen to me and if they don't then I will just carry on and not let them get me down, and (b) if that's not enough, drop them like they're hot. Remember that other people's "supposed to"s (you're supposed to be silent, you're supposed to be good, you're supposed to take care of us not need being taken care of) are not your reality and NOT YOUR PROBLEM. You can only take care of yourself and help to support those who love you and at least TRY to understand where you are coming from and give you room to feel better.
That is my advice. It's really hard advice but following this plan has given me peace of mind. I hope it helps you too because peace of mind is important for fibro sufferers. Stress causes flares and incalculable pains and other troubles. It's simply not healthy for us fibro folks to live with stress and shitty social supports.
I wish you all the best!
AliInMontreal