Hi Vino this a very old zombie thread,
But as you've dug it up & posted as a GP, plus for anyone else interested, I now know exactly what caused my Fibromyalgia & of several others I know with the diagnosis, a few with M.E./CFS too. As you mentioned that you are Hypermobile, it might also be relevant to you too as there is a link, born out by animal studies & the number of people I've come across with both conditions & improvements seen in hypermobility when it's treat.
Pernicious Anaemia/Functional B12 deficiency, frequently missed by & a huge amount of ignorance amongst doctors with this condition as too much store is put on the blood figures over symptoms. I'm adding a link that has all of the good info, including guidelines in one place. Plus a symptom check list.
My daughters B12 was well in range, yet a therapeutic trial of B12 injections got her out of a wheelchair, walking & back in school again.
Turns out my serum B12 had been clinically low when she was born, helped along by a NO overdose & low normal or borderline low ever since. Yet I was still written off by my original GP as a complainer who couldn't cope with getting old & a new baby 
Too late for full recovery for me, plus CKD means I couldn't take as much as I need to heal nuro symptoms, but I've seen improvements.
I'm currently battling with my brother haematologist for his treatment, his ignorance over this in a field he specialises in, is gobsmacking, despite other doctors listening & agreeing, he still keeps blocking the diagnostic "therapeutic trial of a B12 loading dose"
Please read up on this stuff, we understand that you don't study much on nutrition in uni, but we need more doctors who understand & treat this correctly. People are dying because of ignorance in this condition.
Thiamine deficiency & fixing that with high doses of it daily, has also cured hand pain I was told was osteoarthritis Too, plus other improvements. Low potassium has made me jumpy & prone to panic attacks, violent headaches, over heating & more. A supplement almost gives me, my true self back
Turns out I also had gastritis caused by h.pylori infection& gallbladder disease, which has contributed on my problems absorbing nutrients. All missed for over 13 years & 3 GPS.
I hope some of this helps you & others. There's a great Facebook group if you'd like to learn more, I'm sure they would love to have you on board. I can recommend Sally Patchcocks "could it be B12" & "what's wrong with my child" books on Amazon, these were a godsend to us 
https://www.b12deficiency.info/