What could this be? Please help.?

Question

Okay i just go toff my period about a week ago or 2 and i have my period for 5 days every 28 days and latly i havent been feeling good latly like ive been having really bad cramps in my stomach or w.e u wanna call them. And my last period was 6 days instead of 5 for some reason and ive been getting stomach cramps every day for about 2 weeks or a week and a half. And ive also been getting really bad headaches and i feel like im about to get sick everyday a lot. But ive never had s*x if that matters. And im 13

Do you guys have any ideas on what this could be?