Period Probs

So I went without a period for about 2 months then decided to take a pregnancy test, it came back negative and then I went another month without it. Then all of a sudden I got my period. And my god it was the heaviest it has ever been, but I'm still on my period 16 days later...(still kind of heavy on some days). All in the 16 days, I've started and stopped. I'll be "off" for 2 days then it starts again for a couple days and so on. Should I go to the doctor about this? Or is it normal since I didn't have one for 3 months?? Help!