It's quite unlikely that you will be pregnant, nevertheless there have been documented cases of women who have quite irregular ovulation and even during their periods or very close to it have become pregnant. Just to be sure it's better to make a test, as well as it is always recommended to use protection, even when one is certain the period is coming or it has just ended.
Well first to be sure, you have to do a pregnancy test. Secondly its quite not common for girls to be pregnant when having sex during their periods. But to be sure, do a test. Thanks