hi! sorry to hear that you're feeling emo... :-P
I don't think there's a right answer to your problem, but I think I kinda can understand your point.
first of all, I know what it is like to grow apart from your friends back home. I mean, it was the same for me and I just stayed away for 6 months for erasmus, and it's exactly the same for everyone I've known who's been away for some time. I don't know you that well and I definitely don't know your friends, but it might be difficult for them to understand the way you've naturally changed while being so far away.
and... it would be normal for you to feel (even unconsciously) tired of japan... a friend of mine who's been studying japanese at uni, who loves japan, who studies like crazy to always be the best at it, and who was accepted for a one year study exchange at keio university, I mean, exactly the type who should be happy to live there forever... well, when back in italy, he confesed that he should have come back at least once in the previous year, just to take a break from japanese people. he said in the last period he hated them!
it's not an easy country... (^_^)'

but yes, try making new friends, that's always a good thing!

and don't worry about ikkyu, many people say it's quite useless. well, if it's just a challenge to yourself, it's totally different... in the meantime, ganbatte for nikkyu!

(I LOLed at "kochajin+toma" on the blackboard!!!)