I need help!!! My Aunt Flo's been here for over a week!!!?

I know that this is very private information but I always come here for answers because strangers are more likely to tell you the truth than people you know. I'm a 19 year old female and have been having my menstrual cycle since age 11 ( i know that's early). I didn't get my period for a while --4 months-- and didn't think anything of it.. just thought I was lucky. My Aunt Flo recently came to visit about a week and a half ago but its still on. I know for a fact that isn't right and I wanted to know if anyone would tell me what the problem may be. Help!!! I'm desperate to figure this out!!! I miss with my boyfriend lol ;)