Hi mate, many on here, including me, have felt exactly like your feeling now, so you're not alone on here.
Please go and see you're GP as soon as poss mate ( if you haven't already ) and be brutally honest about how you're feeling.
You've almost ticked every single box for depression in that post.
I know how hard it can be, just to do something as simple as making an appt with your GP, when you have zero motivation to do anything at all, but the sooner you get the ball rolling, the sooner you can take steps to getting better.
From the post where you described your relationship with your girlfriend, she was only ever going to make things worse for you, due to her own problems.
I know it doesn't seem like it at the mo, but splitting up with her, getting out of a destructive relationship is your first step to getting better.
Keep posting mate, remember you're not alone on here x