Homesickness is a very normal, but sometimes very painful experience.
It's your first week of university, you're meeting new people, familiarising yourself with your new campus, flat, house, bus route and local watering holes. Your first week you're winging it, you're jumping at every opportunity, reading every 'freshers' survival guide and you're moving at rocket speed...
If I am lucky enough to be able to afford a holiday, no matter how carefully I try to tailor it to my idiosyncratic needs, bring my own teabags and chocolate from home, or how desperately I need the break from work, homesickness always seems to strike me, even when on what should be the most perfect holidays.
Even the hardiest of students will struggle to avoid bouts of homesickness at some point during their time overseas. It's a completely normal part of studying abroad, and something nearly all international students will feel at some point.