What Causes Prolonged Menstruation?

I have had my period for a month in half I am 45 and was told many years agothat was going through mental palso so I went and say a obgyn and she just ordered a ulter sound and then a endometrial biopsy she said that they did not get enough samples so she wants to do another biopsy surgical and I don't she never check anything else I did ask for heromine meds what else could be causing it what should I do