Depressed Girlfriend?

Okay, first of all, I would try talking to her. Let her know how you're feeling and if you are meant to be together, she'll understand and will try to change/get help. If that doesn't work, maybe she has changed. From what you've explained above, I'm not sure if that's depression. It sounds like maybe she has changed so I would try talking to her. Sometimes people do change though, and you need to accept that and maybe find someone new. Hope this helps!