What Causes Menstrual Cycle For Almost Nine Weeks?

Hi I have been on my menstrual cycle for almost nine weeks now straight. I have been to my gynecologist and endocronoligist. I have had an external and internal ultasound and many blood tests and everything has come back normal. I am on my 3rd week of sprintec birth control. This is my first time every being on birth control and i am 30yrs. old. I just wish my menstrual cycle would end cause its ruining my relationship. Any other suggestions of why I am having these problems.