Did u find the condom???? If not she should go to the doc.. If it stayed inside of her it could cause a very bad infection! Anyhow, the chances are quite lower when on your period, but not impossible so she could still be pregnant. U will unfortunatly have to wait a month till shes late for her next period if she is. Or if she goes to the doc they may be able to tell by blood being drawn sooner. How old r u?