alexdulcianu said:
If I had to guess, this is a combination of the confirmation bias, psycho-physiological changes, and a few other cognitive dissonance type things.
Basically, you may actually feel more energetic, due to expecting to feel more energetic. Your body responds to what you expect.
But, my more reasonable guess is that your lunacy (get it? I know where "lunatic" comes from, aren't I clever?) has the same origin as PMS: bad statistics work. You're looking back on previous events, and finding a pattern which doesn't actually exist (also called type-1 error, or apophenia to be pretentious). You're looking at a series of data, and finding a pattern both based on your recollection (usually faulty) and the human desire to find some sort of pattern to any series of information (always faulty).
On the PMS thing, before I get flamed for not understanding biology/women/ect., in studies where women track their moods on the actual day (rather than in hindsight), there is no significant difference in mood/moodswings/depression/agitation on days when "PMS" should be happening than on any other day. It's a random distribution which, due to the aforementioned confirmation bias, has come to have an incorrect pattern attributed to it.
Basically, women remember when they're agitated and on their period. You remember when you're excitable and it's a full moon. Women forget to account for times when they're agitated and not on their period, and I'll wager you're not taking into account the full moons you've been calm, or the other times you've been excited.
We like pattern-finding, and we're often wrong about it.