im a virgin and a day before my period i had oral sex where there might be a chance that precum came into contact with my vaginal area. i was expecting to have my period the next day and when it got delayed by more than 24 hours i panicked and took an oral contraceptive. The pill was taken after 40 hours. What are my chances of getting pregnant? should i be worried? also, is there a way for me to know when i should be expecting my period again?