Suggest Treatment For Amenorrhea

I am a 31 yr. old female and 4wks. after I had my daughter my menstral period stopped and I have not had a period in 11 yrs. I have had tests and the results came back that I was in the early stages of my cycle a dr. said it was just because I was over weight but for 11 yrs.!?! what could be the cause of me not having a period for 11 yrs.?