Ask your doctor for dicolfenac. Take it for 2-3 days before your period starts and during your period
Failing that, do the same with a NSAIDs such as aspirin, ibuprofen etc. Period pain is usually caused contractions of the inflamed uterine muscles.
I used to suffer from epically bad period cramps (as in, like, labour-levels of pain, accompanied by vomiting, fever, passing out, diarrhoea etc) that if they came on in public usually warranted a trip to A&E and intravenous opiates and/or anti emetics and/or anti-inflammatories. After I changed my diet, I still get some cramps, but not once these horrifyingly painful attacks that used to blight my life! (I'm on primal/paleo diet, if you're interested. Although it's possible I grew out of them, I guess)