What Causes Heavy Bleeding During Menstruation?

Hi I'm 32. I'm a week away from my period, but am suffering heavy discharge this past week, I've been really tired and my boobs are sort to touch... I've been peeing a lot to and had period type cramps for 3 days last week... I had unprotected sex on the 7th 14th and 17 the... I had a neg prey test?