I Have Not Had Regular Periods For Years,only With Birth

I have not had regular periods for years,only with birth control, finally get to a doctor.after tests my testrome levels are high.so I'm put on metformin 1000mg day after a month I have my first real period in ages in October 2016 (light the first day then heavy the next 3days then spot a day. I have been trying to get pregnant so last month I download the ovulation calender. When it showed high fertility ,I had sex every 2days near the end I took a ovulation test it was positive.so I had sex again ,I waited 2 weeks as it suggested to take a pregnancy test it was negative, later that day I started which shouldn't for another week and this period is different its lighter then normal.