I understand your point and I see where this can contradict my statement. Self harm is often considered counter productive, and you'd be right. In this case it could be a few things:
-Your brain cannot process a large amount of emotion and perhaps seeks a way to process it through self harm (my answer is not definitive, everyone has their own reasons and please take everything I say with a pinch of salt)
-The need to remove yourself to preserve your own species because you could potentially cause harm to others around

Or simply
-No other options are left therefore you should not exist.

I hope that if you DO feel this way that you get through it and that the future brings you happiness. :)