Good luck! I would have been anxious about studying abroad too. I'm not sure if it's the being in a strange place or the actual coursework that's causing more anxiety, but either way, I would say that 3 weeks will go by really quickly, even if something goes wrong, it won't be the end of the world, and that relaxing, accepting you can't control everything, and just focusing on the moment and not worrying about what might happen will help.