?? Anyone know

My last period was weird. It was April 21-May 1 and came back lightly from May 7-May 15th. I had EWCM and ovulation Cramping May 27th & 28th. So I am 3 days late. But still getting BFN. My periods have been regular for a while with CD28-30. Is there a chance I could be pregnant? My doctor told me to go by April 21 and the beginning of my last period. But I figured I would have gotten a BFP already? I didn’t track ovulation I just went by EWCM so maybe I ovulated a couple days later? Heck I don’t know 😭🤷🏼‍♀️