I am, as many know, an odd combination of optimism and cynicism, of generous believing and scathing critique. So, normally, the saying "If it walks like a duck, and quacks like a duck, it's probably a duck," is not an axiom I live by.
However, replace the word "duck" with "PMS," and my moodiness this past week becomes crystal clear. I kept saying (to therapist, GF, anyone who would listen), "This low mood, it feels a lot like PMS--I feel like crying over the dumbest things!"
Well, there you go. Sometimes, the search for deeper meaning is misguided.