In the Wilderness
Being alone on a desert island can really push your nostalgia over a cliff. I hope you have something besides your own thoughts to keep yourself entertained and forget about home for a while. Activities like talking/playing with your companion, improving your shelter or even trying to find treasures underground are great ways to make nostalgia go away.
In School
School can be stressful, and everyone knows it. When you feel extremely bored or anxious, there are lots of activities for you to keep life fun. Taking a nap, for example. But set time limits because a nap could become a full ten-hour sleep. Going out and playing sports is a great way to keep you both fit and entertained. And last but not least, using the internet for social media and video games. But if limits are not set and you overdose, your studying efficiency will decrease, so be careful.