Right, though I personally think you shouldn't really post such personal information online, I can understand why your panicking - desperate times call for desperate measures and I can relate to that.
Before you do anything else, what you need to do is take a deep breath and acknowledge the situation your in. Don't try and panic over it - just let it settle in your mind, and accept your situation. From there, you can start to move on to solving the situation, as much as it can be solved.
For the time being, don't try and ponder whether she did it on purpose or not - the fact is is that she is pregnant, and the child is the first priority, not pointing the blame at someone.
A depressed mind can't really do much in such a pressurised situation - you might want to find a councillor, or, if you can, take a short break from all of it - go to a beach or somewhere quiet, but only if you can.
So, the kid is going to happen - from here on out, your probably gona want to consider how you can help the child to the best of your abilities. Save up money, even if its a small amount; try and find if your entitled to any grants, the government might be able to help you, depending on what country you live in; ask for advice from anyone you trust about bringing up a child.
Look, mate, you may not want to be with this girl anymore, but the truth is is that you (frankly) fucked up, and the child is the result - he/she doesn't deserve to grow up without a father because of your mistakes. The biggest piece of advice I can give you is stick with this. This is possibly the most important moment of your life.
You may hate the idea of having a child right now, but from what I've heard from many, many parents is that the birth changes everything - keep that in mind.
Unfortunately, I know very little about children in my personal experience. I will also send a message to someone on The Escapist whom I know is very good at giving advice to those who are in troubled situations.
Goodluck.
edit: oh by the way, sorry about the unwanted lecture - frankly, you need it.