I had my first extreme fatigue/brain fog time about a month ago. It was awesome. I do freelance work at the computer; it was like pulling teeth. Even to sit up in my chair was a challenge. I found that at the end of the first week, I had logged 3 computer hours. I was totally unable to multitask or to keep 2 things in my mind at once. I couldn't remember numbers at all. My back was really painful. Then, 4 days ago I woke up normal. No pain, lots of energy. So I went hiking, cleaned the house, finished my work projects and felt good. Then this morning, back to the slog. My muscles were stiff after I used them. Not thinking too well. The couch beckons. The only thing different was that I awoke in the night feeling really hot. Without the covers, my skin got cold but not my body core. No fever, just hot. Maybe that's correlated. Tired of doing correlations with diet, behavior, symptoms, but determined to see if I can find triggers for these episodes and reduce them.