Bleeding 2 weeks early... Period, pregnancy, or miscarriage?

Im 29. My periods have always been irregular (always longer than 4 weeks) until two 6e54cyears ago when i gained some healthy weight and they became like clockwork of 5 week cycles (+/- a day). Ive had my regular period last month 16th-20th, 5 days after it ended I've had sex a few days in a row (knowing I'm not due to ovulate for at least a week). Then 4-5 days after sex my boobs got very sore, I've never had that before, like very sore... It lasted for 2-3 days and then went away, also during that time i felt very mild cramps like my period was going to start, they lasted an hour... I took an ovulation test, the stipe was faint, but there was two. Two days after that I got my period, it being two weeks early. Usually i get a lot of pain 1st day, and lots of blood clots and its always kinda dark. Now, pain was very mild, its bright red and almost no clots, same flow as regular period. What is happening to me? My husband and I been trying to get pregnant for the past 6 months...