Hi just to give those of you with severe brain fog hope. When I was in the extremely severe stage of C.F.S ie unable to do anything apart from lie down all day, ,more or less shut down,I had extreme brain fog. I'd been like this for about 7 years when I woke up one morning and it was gone! My head was completely clear! Unfortunately the other symptoms have remained with me, but I tell you losing the brain fog was totally liberating!I gradually managed to get back on my feet. I have no idea why it suddenly went, the only med I was on was one to help control Orthostatic hypotension which they give to patients after operations,and I'd been on it about 3 months.Anyway hopefully your fog will lift too one of these days!