Thats a toughie. I've been there and I hate to say cutting off contact is probably best, because it's going to hurt like a bitch, but it probably would help. When you're that deep into someone and its hopeless it doesn't leave much room for new loves that hopefully aren't doomed. Have an internet hug.

Few questions before I give an answer.
Have you been in an emotional relationship with a depressed and damaged individual before?
Have you considered that maybe your love for her is based on the normal human desire to be a hero and fix her emotional state.

I’m concerned that your initial view of her started with her crying all the time. If that’s your first recollection of how she is, perhaps that’s why you have these feelings of love and nurturing desire.

Yeah, I cut off contact last night...