I don't want to be with my girlfriend now she's being promoted to a new position at our job.
Why do you not want to be with her?
She's practically forgotten about me ever since that promotion happened. I have better things to do than sit around waiting for her.
I understand you might be feeling abandoned, but her success doesn't mean she no longer cares about you. You should be happy for her. You need to share your feelings with her, let he know how you're feeling about the situation.
I think I'm going to break up with her.
Are you that jealous? You shouldn't end a relationship over something so small. It's childish and soon you're going to keep doing this to every relationship you're in if you don't grow up now.