So I’m currently freaking out, I had sex on my fertile day (December 14th) spotted December 30th just enough to wear a pantyliner and it ended the next day. My last regular full menstrual bleed was Nov 24th. My January period is stating to be 11 days late (latest I’ve ever been). Recently I’ve developed shellfish allergy and I’ve never been allergic to seafood. Taken two tests both come back negative.