So Confused

sadly I had to have a D&C; on Monday the 18th. I was suppose to be 8 weeks but baby measured 6 weeks 1 day which sadly is the same measurement we were given (with heartbeat) on September 1st. We dont know what happened and this is our 2 MC. Doc thinks its due to low progesterone due to me having PCOS. Anyway doc told us we can try again in a month. Only problem is, I don't know if my ovulation schedule has changed...anyone have an idea on how I should track it again?