No period. Negative tests. What is happening?

Sa

My period was due dec 6. I haven’t been tracking my ovulation date so am basing that period date off previous months. No pregnancy symptoms except breast enlargement.. negative HPTs as of yesterday morning. No bleeding. Did I just not ovulate or can this still be an early pregnancy?! What’s the latest you’ve had a positive HPT? I want to start using this ovulation kit but since I don’t have an AF date I don’t know when day 1 is! Btw ovaries looked fine on TVUS a couple months ago