The shot

I went On the shot in Jan of this year. I didn't get my period for the two and half month. But I took tests and it said no. And I finally got my period but it's lasting for 17 days and counting and having blood clots daily some of its its brown with no blood. I have more blood clots on it then off. Has this happen to anyone else? And should I change birth control? Or should I talk to my doctor about this?