What the hell does this girl want with me?

Your her friend, aren't you? But I guess you want more than that. There's no hidden agenda. She just feels comfortable with you. Yes, there maybe little or no chance of being more than friends, but you are in a unique place in her life. She trusts you with who she is. If that's not enough for you, then let her know. You can't be friends anymore. No more hugs, or late night talks, or happy smiles for you. Tell her you don't want to be her security blanket anymore and find someone else to be her emotional tampon. If that's what you want, of course.