Added on Thu Feb 09 2017
No, it's not in her head! Menstruation is the very part of women but what some guys don't understand is that it hits them with flurry of hormones floating around and bringing about total disturbance in their body. It's completely natural and not under their control anyway. For some, it's probably an easy process while some has to go through periods of depression, horrendous cramps, bloating, food cravings, and of course, an emotional roller coaster inside the head. And yet, some guys couldn't stop themselves complaining about being victims of their mood swings.
So guys, if you cannot understand her state during those days, at least save yourself and her from the worst statements above.