BAD CRAMPS ; please help?

I know how you feel- I get horrible cramps that sometimes I can't go to school because I'm so sick and in pain. I'm only thirteen, but I've had my period for three years and I know what works for the worst cramps, because I'm young and a lot of my friends don't have their periods and I don't like to be around them when I have cramps so I have to do something about them. People say that Advil and Motrin are the same, but honestly I think Motrin is better when it comes to cramps. I take two pills every 4-6 hours and it usually works for me. I also like to put a heating pad on my stomach and back for like 5 or ten minutes. Another thing that is like a miracle worker for me is doing certain stretches. One stretch that helps is to lie down on your stomach and then push you upper body up with your arms, almost like your about to touch your feet to your head. Also, if possible before school, try to exercise a little. Maybe do the treadmill or dance or try anything that involves physical activity. At first, trust me, you don't want to do it. But after you feel great, your cramps go away for a couple of hours and with some Motrin, it's like you don't even have your period(: Hope this helps!