Dynamics of relationships works in mysterious ways. Maybe not as mysterious if a pattern is emerging.
A lot of thought has gone into the whole breakup thing and you can read a part of it from psychological point of view at:
I am pretty much going through the similar state of life but have been through it before and it is not hitting me as badly as before.
I think it hurts you even more when you feel that the decision has been forced over on you or you feel that you have just about no control. You can obviously turn the table around by being so sorry about the whole thing. After all if someone calls a relationship of 2 years useless then it was not worth it to begin with.
Now what is more important is that you understand what you want from the situation, do you want to move on or do you want the relationship back, irrespective of what others think about it. Once you know what you want, you will at least have some direction.
I would recommend a movie that helped me get over the breakup once, it is called "Getting Over Sarah Marshal", it is about a guy but I am sure you will be able to relate with it.
I really hope that you get over this difficult time and get the best of life :)