My best guess on this one, if it was caused by fatty foods, is the butter I had on the seafood I ate for dinner. Not that crab and shrimp are low fat in and of themselves, just that the butter adds a layer of extra nothing but fat.

There's part of me that would rather this were just a fibromyalgia flare. That would be unpredictable and untreatable but not necessarily likely to recur if I make misstep in eating. Food is fraught at the best of times.