Why my period is so long?

How come my period lasts 7days like don't I suppose to b dead. And I feel like I'm pregnant when I'm on. I'm grumpy, I'm horny, I'm sad and all I want is spicy foods. I guess the weman who periods that last 5days fiend for chocolate. Why do I always throw up and have the runs as well. I've never been pregnant before, and if this how it feels then I don't want any parts.