Dear Ella if you are still having periods after unsafe sex, then there are virtually no chances of being pregnant. But just to be on the safe side, it would be wise to take a home pregnancy test. Please use condom next time. And headache may be because of stress or tension, or anything else, you should consult a registered doctor about it. https://lovematters.in/hi/resource/safe-sex https://lovematters.in/hi/pregnancy/home-pregnancy-tests-dos-and-donts If you would like to join in on a further discussion on this topic, join our discussion board, ‘Just Ask’ https://lovematters.in/en/forum