I've been getting hormonal migraines ever since i was 11, and it was awful back then I was put on the pill, but I didn't like the way it made me feel, so i stopped. I'm not a huge drinker, but what has helped for me is chugging water like its going out of fashion (at least 3 litres a day) in the days leading up to my period.

Mind you that didn't help for the week and a half long creme egg induced migraine i got a few weeks back >_>

I'm lucky, mine are not nearly as frequent as they used to be, and drugs work when I need them. I've found that real ginger helps a lot, not for just for the stomach (which isn't usually an issue for me), but for the pain. I make ginger tea (Yogi Tea makes a great one) and eat crystallized ginger. Now that I'm restricting sugar, I should probably go buy some sushi ginger. Several years ago when they were much more frequent, I was taking ginger capsules every day for prevention.