9 Day Period

Thaera

So I have been on my period for 9 days straight. I don't know what is going on this is the first time it's happened. Throughout the 9 days my flow would be really heavy and others very light. I've been seeing my period since I was 9 years old, I'm now 18 and it had only lasted for 5 days every time. I don't know what the cause is and I'm getting very worried. Does anyone have any advice on what it might be and how I can get rid of it???