unprotected sex 7 days after period

Women ovulate between 10-14 days after their period so generally it would mean that you are not in a big risk but the sperm can survive for a few days so there is a possibility, also every woman is different and with no forms of birth control you have a 20% chance of getting pregnant.
It is way too early for you to find out but I would wait for your next period, if it is late take a home pregnancy test. Try not to stress yourself too much because that might make your period late.
Good Luck!