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."
Zone diet on and off for several years....worked, but too much focus on exact meal composition
Primal since July 2010...skinniest I've ever been and the least stressed about food