Beware the Crimson Tide. Look for the signs, which may include: Animals acting strange, a low rumble, raining frogs, the smell of rotting flesh and alerts from local news outlets.
My girlfriend had endometriosis so now she is "fixed" but she still has some gnarly mood swings.
Her kids are the first ones to know she is having hormonal issues.
As a girl I can say I do act out when on my period, but later i'll realise what I did and apologise. It's not as much being a bitch as being easily irritated and wound up.