HORRIBLE cramps and feel like I’m gonna faint?

Hey, 

So around my period I’ve always gotten TERRIBLE cramps. I can’t walk, and unable to sleep the pain is so severe. Anyways this morning when I woke up I felt bad cramps so I took a Motrin before going to school. I went to school and was fine until 12 when the cramps came back and was in a lot of pain. I kept getting heat flashes and I felt faint and almost passed out but then I was okay. I just want to know why I feel like this because I really don’t think it’s normal. I’m 17 and started at 11. My periods are regular and I’m due on the 24th. But why do they hurt so bad? And why do I feel like passing out? What should I do? Thanks.