Thank you for posting your question here, I will try to answer it to the best of my abilities.I pill
doesnt stay in your system for a week, its already gone, as such I recommend you go to your doctor and ask him to prescribe you some ulipristal acetate, it is an emergency contraceptive pill
that works upto 5 days after having unprotected sex.
I recommend you start using contraceptive pills, that way you wont have to worry like this. Also your period can be earlier and later than usual depending on how stressed you are, so that can explain why yours is early this month.
I hope this answered your question.