Did I just find a problem with my fertility?

My cycles can vary between 27-31 days or so but I feel like that’s still pretty consistent. When I started trying OPKs is was recommended to start testing around CD11 and test for 5 days to catch ovulation. But when I did that I never got a positive....decided to keep testing, and FINALLY got a positive on CD 19. I thought it meant I would be having an abnormally long cycle that month but nope, AF came 9 days later.

I’ve continued to track OPKs every month since, and consistently I’ve gotten my first positive as early as 11 days before AF inevitably starts to as late as just 7 days.

I’m so confused and worried, I thought O was supposed to be 2 weeks before the next period - most places say an embryo wouldn’t even implant until like 9 days after

ovulation, but if that’s true I don’t see how I can ever conceive naturally when my uterus is shedding its lining before a fertilized egg can even get in there.