I had to check to make sure that you weren't my mate from 6 months ago, cos I can tell you're pretty similar to him just from these few posts in this thread. You come across to me as the type of person who just says things, in a "this is the absolute fact" kind of way that you just say them confidently without questioning yourself, like "Trust me, I've tried, I have a lot of willpower but it's all focused on making me not go murderous.", "If anyone lists any of her faults I just go insane and attack them.".. and maybe if you were to sort of think more about these things then you'd see that these aren't really as true as you state them.
Perhaps if you were to realise that, no, she isn't the only thing making your life less depressing, and no, you won't attack friends randomly who may try to help you and no, you actually have more willpower but you're not using it, you may be able to solve this problem a little better.
My mate solved his problem by finding another girlfriend. Don't think the pills or counselling beforehand made him any different, prolly just enforced his idea that this is such a gigantic deal.