When did you get your positive??? AF due 12/20

I see many people get positives days before their missed period. I got pregnant in October and got my positive the day of my missed period.  I tried a couple days before that and it was a BFN.  Unfortunately I miscarried so we r trying again. My next period is due tomorrow 12/20 I ovulated around 12/7 and we BD the 4th, 5th & 6th. I took a test yesterday and today (1 day before expected AF) and both are BFN. Has anyone not received a BFP until after their missed period? I know HCG levels multiple every 2 days or so.. Trying to stay positive but it's discouraging.