I've always had really horrible periods and they are still fairly horrible even with a good Primal diet. The cramps and nausea are a lot less now though. The things I think have helped me most:
Magnesium supplements - these aid peristalsis (movement of muscles in the bowel) and also reduce painful cramping.
Omega 3 - I eat fish and also supplement, taking a larger dose during my period. I believe a high fat diet assists the natural cleansing down there.
Herbal teas - Marigold/Calendula is a diuretic, it helps with bloating. Ginger tea, helps with nausea. Chamomile is calming.
Chocolate!!! I try not to cheat too often but I think chocolate is an essential medicine at that time of the month!
Start weight: 238 lbs (March 2012)
Current weight: 205 lbs (July 2012)
Loss so far: 33 lbs!!!
WOE: Primal + IF
Movements: Hiking, sprinting.
Goal: to see my abs some time in 2013!