Studying abroad

I studied abroad and just got back and my period has been late for almost a week now. Seeming that I did not have sex abroad, unfortunately, I do not think there is a baby in there. Is it because I traveled over seas? I know that when I had just gotten to France I started my period and not even a week later it started again!! In the middle of class also lol so shitty. Anyways, is it because of traveling??