Overly pathetic, what can I do?

hello,
i need to ask some emotionally embarrassing advice.

I had a crappy childhood that scarred me for life and a long series of really bad relationships, mostly because i didn't know how to protect myself.

since a few years i stopped keeping the door open to negative persons, i am trying to deal with my emotional neediness, overall i think i am doing well. I still feel a bit immature for my old age, but now at least i know what i want: to love and be loved (scary, isn't it ?;-) and i m not afraid to say it.

now, two weeks ago, my flatmate of 5 months made a pass at me, had been strange (extremely attentive, saying i was a very special person to him etc) for two more weeks before than, and i made the mistake of saying yes, it was a mistake because he was going to leave for four months for a course.

Now he is away, calling only maybe once a week, and I don't know what is happening to me. I can't stop crying, and I know it is psycho but i don't know what to do. I didn't like the fact that he made a pass just before leaving (he said he was doing it so that I would remember him in this period of separation), and the fact that he is not calling so much, no email, no nothing is hurting me to death.
I tried to stop this thing, after he did not call for 4 days (and he said he would call) i did not answer for 3 more, and wrote to him that i deserved better.
he immediately wrote, called etc saying it was a misunderstanding, that he wanted "something with me", to "know me better" (we were in the same house, but not much sharing the same life, i was away most of the time), but now he is not communicating again; also i expressed the hope to see him, and he doesn't want to come visit and doesn't invited me either. Still, he keeps repeating that he likes me and is going to come back.

Now: am i being oversensitive? anyway, I am like this, that is, too sensitive, and this thing is hurting me too much. How can I cut this superficial relationship? Don't you think that, if he really cared about me, i could just say, this is too much hurt, I can't stand it? And he would DO something about it.

OK, please tell me to get a grip. I have a life, only i just can't stop crying. And the idea that he is coming back and we will have to live in a small community shoulder to shoulder is driving me crazy. He wants me here, but if he doesn't want me long-distance, i don't want to do something just because it is convenient. Please tell me what you think about over-sensitive girls, how scary are they. One point: after the first rocky days of a relationship, i usually calm down and stop being so needy and annoying. Also i try not to nag, and just explain calmly that i have trust issues and please just do things right so that i can build some initial trust.
I know, this is SOOO pathetic. But wouldn't a guy who cares just deal with it? OK, over-the-edge pathetic. This is why I m curious to hear a guy's advice, because women's i know already.