Can you tell us what happened? Do you suffer from depression, or what?? What's going on? I'm sorry if you posted it before -- I haven't seen it.
It does sound like you need treatment. Can you see a therapist? Call your doctor and have him refer you to a good therapist. You won't regret it and it will make a huge difference.
Perhaps if your girlfriend sees that you're getting help, it might make a difference. Maybe there will be hope of getting her back -- and maybe not. But even if she doesn't come back, you'll at least have gotten treatment and will be healthier for it. You DO need to see a therapist, regardless.
So call your doctor or see him -- and get the referral. It's the best gift you can give yourself. God bless and please take care. Hugs, Lee