What Causes Delay In Vaginal Bleeding Post A Protected Intercourse?
September or October?
Do you mean you were supposed to get period on 13th September? If the expected date is otherwise (as you mentioned) 13th of october, then you should not be worried about pregnancy. There is no medicines required, just wait for period. However if you have missed period since 13th september, then you should be started on meoxyprogesterone pills.
Let me now if you need clarifications.