Irregular peroid for over two weeks,now i am bleeding so much and pain.?

so i have have my recent peroid for over two weeks it has been normal,aside from it would stop one day then start the next day sometimes. These past 2 days i have been constantly been bleeding large ammouts. a tampon/pad will littarally last me about an hour till blood is down to my knees. I also have alot of small blood clots coming out everytime i use the bathroom (about the size of korn kernals). what could be wrong and what could help?? also have some back and stomach pain but its barable. (last time i had sex it was protected)