Suggest Treatment For Extremely Painful Cramps And Very Light Bleeding

Hi, I get extremely painful cramps but I barley bleed. My cramps begin about 4-5 days before my menstrual cycle begins all the way up until the last day of my period, which usual last 5-6 days. I barley bleed if it wasn t for sanitary reasons I d be able to keep on one pad all day and still it wouldn t get nowhere near full. What is wring with me?