BFN at 15dpo

I always get AF 14 days after my positive ovulation test. I got this cycle's positive on the 14th so I expected AF on the 28th.

Yesterday, I took a pregnancy test. Negative. Not even an indent, faint test line or Evap. Nothing that could be even a slight maybe.

AF is 2 days late. If I'm not pregnant, I would at least appreciate punctuality from AF...