Estrogen would be my guess, as I've read that fats cells not only make estrogen, they store it, and when we lose fat estrogen is released.

It sounds right to me, as during periods of weight loss, I definitely experience high estrogen symptoms, and the symptoms you describe are or at least can be high estrogen symptoms.....
sol

This is what I was gonna say!

Also, you are not alone. I'm finally experiencing PMS for the first time in years.

hi there... you may have a thyroid disease. there are some threads on this board about that. it seems like thyroid diseases are extremely undiagnosed. you also may not be getting enough fat - 75% cals worth of fat. this can stress the body out and make you produce cortisol, which might also make you have those emotional fluctuations. lc is a long learning process.

http://www.krispin.com/magnes.html#Deficiency
also, magnesium deficiency can cause extreme emotions.