Ok...my girlfriend started her period last friday...that saturday night, we had sex unprotected. (stupid I know). Her period is already over but today she was surprized to notice some spotting. She said the only other time that has happened was when she was on birth control. She got off due to an allergic reaction to it. I wondering what does this mean? She says she can't be pregnant cause shes bleeding but im not sure. whats OT think.