period for over a month

So in April I had a long period due to missing it the month before(about 10 days). Then 2 weeks later I got my period again. I have been bleeding for the entire month of May. The first week it was heavy, now it is light, but I still have clotting when I use the bathroom. I'm getting concerned because it feels like I have been bleeding for 2 months. 
What could it be? Every time I think it's stopping it starts up again.