have you tried talking to your doctor about taking birth control? most of the time, painful periods are caused because your hormones are so out of whack that your body doesn't know how to keep up. most forms of birth control can help with balancing out your hormone levels so that you don't feel quite as tired, moody, or in pain and can even cause you to have lighter periods. i'm not on birth control now, but i wish i still was because my periods always have me run down and feeling terrible, though thankfully they're not as heavy as they were when i was younger.
other things that can help are the usual sort of things: advil or midol, hot compresses or heating pads for your back and/or lower abdomen, plenty of water, dairy products (milk, cheese, plain yogurt), and i personally suggest chocolate covered pretzels.
i had this most of my life, im alot older now and dont have periods, get doctor to check your not anemic, but my daughter has same thing, floods everytime, sometimes it can be caused by fibroids in the womb too, anyhow see your doctor they will help you.
I went thru years of painful, heavy periods and DR did not have any idea what to do. I finally went to another Dr who knew how to treat the problem- it was fibroids, three big ones. I was scheduled to have them removed surgically (very easy and simple outpatient) and have not had a problem since.
since you are young it may not be the same problem, maybe research endometriosis.
hope you get better!