I hate to tell you this,
ellehatesweddings, but most (not all, though) guys will always laugh at toilet jokes! Anyway, welcome to our slightly crazy thread!
Your situation is a tough one. I was in the same position as you a few years ago when my TC moved to a different state. I have liked him since 8th grade, and although I have been out of school for a few years, I still think about him quite often. But anyway, as for dealing with the situation, you can do a couple of things:
1) Try to get in contact with him. Just thank him for the recommendation letter and say sorry you didn't say goodbye. You might find you get some closure (if that's what you want).
2) Try not to think about him. This one hasn't really worked too well for me. Although I've gone on dates with guys around my age, I keep comparing them to my TC. I've said this before, but I think that because we often want what we can't have, we tend to 'idolize' (for want of a better word) whatever it is we don't have (in this case, our TCs). Ignore the whole situation. Pretend it never happened. Some people would say that you're young and you'll get over it, but I don't believe age is an excuse for anything.
From my experiences, it does become easier to ignore the whole TC issue if you don't see him for a while, but when you do see him after such a long time, the feelings come back. I know others in this thread who have found that time/distance separation helps them to move on from their TCs, and they end up wondering how they ever liked them in the first place.
If worst comes to worst, you can always come on here to talk if you're missing your TC and need someone to listen.
inlovewithlove, it's good that you're seeing your TCs again. Maybe not so good about the new principal? What are you going to do about Mr S?
Also, I have a little story of my own, since it's been a while since I've had anything to say about a TC. I've been doing my teaching practicum this semester and I have a bit of a crush on one of the teachers at the school

He reminds me a lot of my TC, but is probably a little younger and maybe even a bit better looking. I haven't had much interaction with him, though he says hi if we pass each other in the corridors. And he holds doors open (guys my age never do that!) I was kinda watching him in the staff room today and I think he may have seen me a few times (oops!) Legally because I'm over 18 and not a student, something could happen, though I don't actually want it to. It's just fun to look! That's one thing I've noticed, though. Since my friends and I have turned 18, older guys (not really old, just older than us), pay us more attention. What does everyone think? Agree/disagree?
Sorry for such a long post - a few big issues in there!