I am a 33 year old woman, 240 lbs, 5'6", married, and my last period was in July 13th. In late August I took a pregnancy test and it was negative. The following I took some other pregnancy tests and still negative. My last attempt was on September 12th and that test came back negative again. My menstrual cycle has always been irregular since my teenage years. Could I be starting Pre-menopause?