Good Day Doctor.please I Need Some Clarification.my Last Period Started

Good day doctor.please I need some clarification.my last period started on the 1st of August.i had sex on the 8th,took d first tab of postinor 2 immediately and the second afta 16 hours.i had anoda unprotected sex on the 15th nd took the two tabs of pistinor 2 immediately to avoid first mistake.i had some light bleeding two days after and it continued for three days.i feel like I should have seen my period by now but stil haven't.been having tender breast for two days now and last night I had another unprotected sex.do I need to take postinor 2 or am I on my safe period.how do I know my new cycle?