Man, I got Deja Vu reading >>1 and >>7. I was in a very similar situation just a couple weeks ago. (Though I'm not sure to what degree.)

The difference is, when I talked to her on MSN late at night about it, she said she would try to be better about it. But I saw no change! She was pretty much the same as always. After this, I started getting depressed the same way you were. I'm ashamed to admit it, but I even cried once worrying so much that the relationship was going to have to end soon.

That's when I had a change of perspective; I just relaxed. Enjoyed myself around her. Loosened up a bit. That's when I noticed that it wasn't really completely cold. When I didn't go out of my way to be affectionate like I usually did, she would start to get closer to me, perhaps remembering her promise to change. The signs were very subtle, but once I opened my eyes I could tell she really did like me. I realized it's just part of her personality to be very 'closed,' but that didn't mean she felt closed around me, and as long as I could accept that we could be happy.

I guess the point is that if she's worth enough to you, as she is to me, you can work through this problem together, but it's probably going to require a lot of sacrifice on your part.