I'm beginning to think SOMETHING happens at about this point. I replied to a post a couple of days ago from someone feeling suddenly hungry after 9 weeks on the program. I was feeling suddenly hungry (and just not quite right) after almost 9 weeks. We were told "EAT MORE" which felt right at the time. But I listened more to my body yesterday as I ate. It wasn't that I was hungry, it was that I was yearning something. It's the same sort of feeling I've had the couple of times I've tried to go vegetarian...I'm eating enough to feel completely satisfied, except I'm not.
I realize this isn't the same thing as the physical manifestations you report, but the combination makes me wonder if this is a point when the body says "this isn't just a SEASONAL thing, this feels more permanent, better shift something."