Hi, Me And My Boyfriend Had The Deed Last Dec.

Hi, me and my boyfriend had the deed last dec. 17 around 1pm. At 6pm, I took nordette 4 tabs at then took the 2nd dose after 12 hours. I am expecting my menstruation today but still there's none. I am also having a dry days as in no cervical mucus at all for about more than a week. I haven't had any withdrawal bleeding after taking nordette.
What could be the reason