OK, if someone makes an incredibly rude assumption about you based on cues that you gave him, and he's 100% correct, then you're not allowed to get angry. You were obviously acting in a way that lead him to come to that conclusion. The right course of action to make everyone happy isn't to become a psycho bitch in response, it's to try and stop being a psycho bitch and control your emotions like a rational human being.
ultimate test to determine if a girl is worth keeping (has to pass both). Remember, the period account for 7 out of 30 (or is it 28?) days in her sycle. That's kinda a lot...
1. is she a psyco pitch on her period?
2. is she a psyco bitch if you comment that she's on her period?
If the answer is yes to one of them, she'll likely tire you in the long run, making you get annoyed by her every time she's on her preiod. It'll strain the relationship to breaking.
Morale: psyco bitches are best left alone so they can't copulate, and potentially produce more psyco bitches