I use an app called "Mood Horoscope" (Used to be called Hormone Horoscope)

It has nothing to do with Astrology-- You set the day and time of your first day of your period then it tells you what is going on hormonally on each day. (Progesterone dropping on day XX etc)

I find it helpful to check when I'm in a mood with little explanation

https://itunes.apple.com/us/app/horm...710914595?mt=8