I think the best way is to keep ur self occupied.. I cant help but get sad if thoughts tend to spill all over.. Everyone has their shares of ups and downs, and its liketly to remember only the lows when u are by yourself.. Keep ur self occupied.. there are always internet, chats, movies that helps you to keep you mind off your thoughts and home. 

IF u are in the States-- they have meetme stuffs . those are groups where u get to meet people sharing your interest. That way u will meet new friends too

Good luck,
Mercy