I've just been addressing some fatigue issues in the last few weeks (more than a year Primal), nothing major, just not quite my normal self particularly in the second half of my cycle.
I decided to try magnesium (read lots and lots about the benefits and relative difficulty of getting sufficient through diet alone) and Vitamin D, this is the big one I think, especially feeling this way in February, seems to be a common theme for us living north of the Equator, and I live a loooonnnng way north LOL!
So, I've been taking 300 mg magnesium (as 150 mg chelated and one osteocare which gives 150 mg magnesium with some calcium/boron/zinc etc) with my evening meal along with 1,000 IU of Vitamin D3 and then with breakfast 3000 IUs of Vitamin D3. I've also included 5-HTP but that doesn't seem relevant to your situation.
Results so far have been impressive, a definite lightening of mood and improved energy and no cravings or energy slump in this PMS phase. My money would be on vitamin D for you, unless you are living somewhere seriously warm year round!
Seeking the natural way in a modern world ...