How long has Plan b delayed ur period?

Hey guys!! I took a plan b last Thursday after forgetting to take my birth control on time (i take Norethindrone, and remembered to take it near the three hour mark so i wanted to be safe) and my expected period was three days ago, but i havent gotten it.

Ive taken two pregnancy tests incase and both came out negative, so im not as worried abt that- just more so curious when my period will actually come?

My last time taking a plan b i had started bleeding about four days after taking it so not bleeding at all so far is new for me!

Has anyone else experienced this??