I figured it out!

I finally know what all the separation pain is all about. All those tears I've cried over the choir, all those tears I know I will cry over leaving some of the people in my current job... tonight after my last Creative Writing lesson it dawned on me.
As I said goodbye to the handful of people I've met up with on a weekly basis every Thursday night, I felt tears spring to my eyes - AGAIN. This time I was not prepared for that at all - I'd only known this group for about 6 months, barely manage to remember some names. How can I feel so strongly about them?
And the explanation was so simple, I couldn't believe I hadn't realized it earlier. Because whilst I treasure these people and what they have brought to my life very much, it is only the circumstances that brought us together. And the same circumstances will tear us apart again. As I left, everyone came over to hug me and made me promise to keep in touch. And I want to. I really do. But the question is, will I?
I treasure all those beautiful stories I have heard from everyone, the laughter we've shared, the tears some of the stories have brought to my eyes - it was part of my life, a very enriching one at that. But as I move on, I somehow know that I will lose these people. Sure I will email every now and then and sure they will email back but I already know it will get less and less frequent over time and after a while it will stop completely. For everything that's bound us together, the writing class, just doesn't exist anymore.
And the tragedy of it for me is that on one hand I want to keep them in my life but on the other hand, others will soon take their place. And I am only mourning their loss because, unlike my real friends, I know they will not be part of my life anymore.

It does help to put it all into perspective... in 6 months I will not feel the pain as much, I will feel the joy of knowing that I was lucky enough to have those people in my life. And it will make me smile and all the tears will be forgotten :-)