It's not uncommon for periods to get messed up when you make major moves like you have, especially if you're excited about it, or it's the first major trip, or whatever...

When I was an exchange student, my best friend had periods every 2 1/2 weeks for the first four months. My first period was two weeks early, and then I didn't have another one for five months.

You'll even out soon enouhg. :)