You say you used protection. Condom? If he had a condom on during intercourse and it was intact when he removed his penis from your vagina, then you were protected. Ejaculating after near you isn't going to get you pregnant. You do not sound pregnant. You can go for a double prevention method like using the pill and condoms both. Periods can be a bit different from cycle to cycle. Stress can play a role in that. And it also could be blood from your hymen breaking. One thing that is helpful is for you to start tracking your cycle. Cycle day one is day one of your period. We normally ovulate midway through the cycle which is day 14 for most women and sperm can live for several days before that. So, we are 'more' fertile starting on day 9 of the cycle. BUT, there are no safe days. It just means 'more likely'. But it is helpful to know this information about yourself. Again, this doesn't sound like a pregnancy situation. Glad you used protection.