I can't say this has happened to me.... but, did you ever consider going to a new doctor and not telling them you have fibromyalgia to see what they would then tell you? It is possible given it's sort of catch-all nature that some doctors just automatically will assume someone that has it is just complaining for the sake of complaining or that there is nothing else wrong with you once it's known you have it because it affects so many things in such weird ways and doctors don't know what to do with patients once they know they have it other than to suggest a bunch of different meds. If something is severe and you know it's not a typical fibro symptom for you, then go to the ER and don't tell them that you have fibro so they will treat you for the issue at hand and not dismiss you. Same with something less severe... if you do try seeing a new doctor, consider not telling them about the fibro (that would also mean don't have your records from previous doctors sent to them either because they'll just see it in your chart) and only telling them about the current particular health issue. If they don't know you have fibro they shouldn't be as dismissive of your other non-fibro symptoms because they won't have that as an easy fall back to blame everything on.

They used to tell me everything was psycho somatic due to my mental health / PTSD dx. Now they tell me everything is the fibro. Even tho for instance my brother has the same back pain I do / fusing but not fibro himself.. I think they just dismiss me of everything also.. :( Medicine is a practice not a science.. Unfortunately they just have no clue. That has been my experience. And so I've learned I just have to do what I think may help and see if it works. And some things have but many doctors and therapists ect aren't so supportive of you "self treating" or "self diagnosing" yet won't do anything to treat you or help you..