My husband has it. Anyone who thinks it's not a real disease needs to hang out with him when he's having real issues with it. It's awful, and he is a tough cookie. A PM&R doctor and a rheumatologist both diagnosed him with it. The rheumatologist explained it being something where the brain isn't getting the pain signals quite right, so certain sensations that are normally not painful are painful for fibro people. For him, Lyrica works and so does Savella, but the Savella has side effects he doesn't like.
Incidentally, he takes the rare Vicodin for back pain (an old very serious injury of fractured vertebrae) maybe once every few weeks to few months, and those do nothing for the fibro pain. He can distinguish the fibro pain and the pain from the old injury and doesn't take pain pills for the fibro pain.
It's hard to make some people "believe" it's real if they don't have the joy of living with it. To me, fibro is like depression where the symptoms show up in pain and tenderness rather than depressive gloom.
By the way, the fibro brain fog is frustrating, too.