Ovulated but not pregnant

I had a miscarriage back on 12/8/19 (first pregnancy), the OB said we can start ttc again on 12/24 or wait at least 1 menstrual cycle for dating purposes of the next pregnancy. We started ttc and I also started tracking ovulation on 12/24. Without a cycle, I ovulated on 1/3-1/4, BD. AF came on 1/17, ovulated on 2/3-2/4, BD, and AF came yesterday, 2/17. When we BD, we bd for a few days before ovulation, on ovulation and for a few days after ovulation. We usually BD 2-3 times a day so I dont know how I'm still getting BFN. So disappointed. I've heard that many women are very/ more fertile after pregnancy/miscarriage and can get pregnant again without a cycle or within the first menstrual after. I've been getting BFN so I just want to know, how soon did you get pregnant after a miscarriage?