Anyhow, listen to poet, she has the idea. It is highly unlikely from the situation she described that she is pregnant. Just stay calm and reassuring, get her a test if she wants, and reassure her that there are alot of reasons her period could have been late, but you are going to stay by her no matter what. Also, yeah Ive been in the situation of girlfriend being a little freaked out (tho she was on birth control at the time, so it was even less likely). And yeah, condoms are like 97-99% effective, so thats the ticket mate.