What Causes Long Menstruation Period?

Hi, I'm 20 years old.

Today is July 18th, I've been on my period since June 26th.

I've been having horrible headachs, my stomach hurts everymorning when I wake up, up around my ribs right below my breasts.

I've always had a regular period until now.

I've looked it up online, but all I find is people talking about birthcontrol.

I have never taken birthcontrol, and I havent been sexually active in a little over 3 years.

Ideas?