I understand your doubts! I have had fibromyalgia for over 3 decades and I still question it. I have also recently felt my symptoms over the course of my life fit Ehlers Danlos syndrome or Hypermobility Disorder. I have no way to get it diagnosed currently and even if I did, there isn’t a cure and it’s still about the same approach. Pacing practices and gentle activity. A healthy, calm lifestyle as I can possibly manage. And try to get treatment for problems as they arise.