Hi. Thanks for asking in Healthcare Magic. You cannot be pregnant as you are having periods. Nausea during premenstrual period is common and is due to the hormone progesterone. But just before the onset of period, the level is both estrogen and progesterone falls and so are not the reason for vomiting during period. Vomiting associated with pain during period can be due to endometriosis, pelvic inflammatory disease or fibroids. You should consult your treating Dr. if you have vomiting with severe spasmodic pain to rule out these possibilities. But if you have only vomiting and not pain and that too vomiting after food, then the reason could be gastritis. Eat small frequent meals. Do not take heavy fatty meals. Also take antacids like Gelucil and Mucaine gel. Do not eat spicy food and take a glass of warm milk. I hope this is useful to you.