Everyone's body is different. You could have benign uterine polyps (very common) which pull on the lining of your uterine wall that cause longer than normal and heavier bleeding. I recommend you see a GYN/OB. He/She needs to know how long, how heavy and determine if prescribing a 1 week med to "restart" your cycle, or do an abdominal & transvaginal ultrasound- to see if you have polyps/or cysts causing your symptoms.
If this is the case, a simple D and C (Dilation and Cutterage- OutPatient Procedure) should fix the problem- for a few years at least.
Hope this helps. You shouldn't have any problem conceiving after.