Code for being on your period. To say you got it, simply say you've found your black stapler. If you're dealing with cramps, say you accidentally hit yourself in the stomach with it. When it's finally over, you've lost your stapler. Only use this if you're around people who you don't want to know your personal business - you should never be ashamed of your period.
You: Oh, by the way, I found my black stapler yesterday. I don't feel good.
Friend: I get you. I just lost mine yesterday.