My girlfriend and I had unprotected sex in the month of August. We decided to use Plan B (second time in her life using the pill). She had her period regularly on September 3rd but 2 weeks later she has been feeling nauseated and headaches and I'm worried that she could be pregnant. Other than that time with the unprotected sex we've been having sex with a condom and the condom has been checked every time for rips and tears and there never have been any.