What Causes Delayed Period While HPT Is Negative?

Hi.. I have gone to the gynecologist last month after my period ( period on 19th Dec) on the 6th Day. Routine scan/ ultrasound showed egg had been formed on day 11th Day & rupture too took place. My periods were due on the 19th of the next month. But I still have not got my periods on 10 days after the period due date. Home pregnancy tests are showing negative. How do I do ?