When my ex dumped me, I always told myself "But I thought she loved me?" and "I'm not that kind of person." Guess what? She didn't care about me like she used to, and the person I became was somebody I didn't recognize. Are you honestly the person that is trying to talk to other girls just to get her jealous? No, you are in survival mode trying to use any trick possible to win her back.
Of course you are going to get mixed signals. No matter how horrible of a boyfriend you were, and how strong of a person she is, when she takes the step to totally remove you from her life, it hurts her too. She is going to wonder if dumping you was the right choice. The best you can do is not give her any reason to think you are the wrong choice. Overemotional, saying things you don't mean, being jealous, trying to get with other girls and rub it in your face. If any of those tricks worked and she was back with you, guess what? It would be temporary and she would break up with you again because all the same problems would be there and neither of you have the patience anymore to wait until they are fixed.
She wanted this, so you give it to her. She wants her DVD's back? You let her have it. All you can do is be respectful of her wishes. Fall of the face of the Earth. If she cares about you in the future, she'll be curious and wonder what's going on with you. Even still, you shouldn't get your hopes up of reconciliation. You think that it was a giant shock that she just dropped this bomb on you, but nobody just wakes up one day and says "Oh yeah, we're done by the way." She thought about this for a while and maybe she wasn't entirely honest with how she felt or you were too dense to read the signs but that's the reality of the situation. She took this step when she felt like she was ready to. All you can do is let her be, and NOT focus on getting her back, but focus on finding your life and your happiness without her.
That way you are becoming the person you were before that she fell in love with in the first place. That happy go lucky, confident person. Right now youre emotions are running pretty high, and the feeling of the hurt and the pain is still fresh in both of your minds. All you can is let that go and give it some time, and if you are focusing on yourself, you aren't driving yourself insane chasing after her. Which is pushing her far away anyway, because it's giving her the confidence to find somebody else knowing that you are going to be there when she needs it.
Is there a possibility of losing her for good? Absolutely, and it's very high. You have already lost her. I think you have an idea of the things you did wrong, maybe getting drunk and acting immature and pushing her away with those shenanigans. So as long as you can improve from this experience, you aren't in an entirely losing scenario. It takes time to really examine where you went wrong and if you are focusing on being a better person and instituting it into your daily life, the next time you run into her, you will exude that you are a newer, better, changed person.
And the thing about focusing on yourself is also realizing that you don't need her to be happy. When you are fully happy with yourself, chasing after her won't nearly as matter as much. You really cannot lose.
Waking up next to a beautiful girl,
Step outside and say hello to my beautiful world.