This is not the one I use but something like this. I wish I could find the one I do use for it is more detailed but you get the point

I like the quicksand analogy. Tell them to look it up. Or really, you don't have to explain at all. You don't have to defend taking care of yourself. Your best friends will be supportive and understand, most of the time :)

All those and moving through quicksand .

I would just say it is you have a nerve condition that hurts your body constantly. People don't usually dismiss "nerves" but they are quick to think Fibro isn't real. And truly, it does have to do with our nerves as well as our muscles.

I just tell people I have Chronic Pain 24/7, and that my brain gets exhausted from processing the pain signals, causing me to be fatigued and forgetful. Mention Fibromyalgia and they are deer caught in headlights or they get the 1000 mile stare.....