low period

I'm feeling down...It's a bad state to be in when I have to teach Christmas lessons to the students. Very bad! I guess the reason that I'm down is that one of my best friend is leaving Japan. It's funny, because I met him only 5 months ago. We were in the same group that came together at the end of July.
Marcos, he is from America , 24 years old, Pisces, loves to run, loves watching Scrubs, downloads lots of movies and Sex and the City for me. We hang out together and get on each other's nerves...but he is the second closest friend that I have here. It's an early reality bite. I guess I knew that in the end we all have to go home. But, when he told me he was leaving in a couple of days, I couldn't help but break down in front of him. We were out at karaoke and I cried. It's like loosing a family member. When you have attached yourself to someone, it's pretty hard to let them go just like that. Then it made me think about all the other friends that I have met along this journey, whom I have to leave either next July or after.
I am so confused right now. I don't know whether I should stay for another year or not. Right now I'm lost for words about how I feel. There's just this emptiness inside that's asking the question, would it be a smaert idea to stay for another year? Or would I benefit from just going home. I don't want any regrets.
Anyways, this is a sad entry, just pouring my emotions out.