What are your feelings about her/the friendship? If your answer is mainly negative emotions, then that's the answer you should pay attention to. Your other questions within this post give me the impression that you're understandably scared about being lonely and without friends if you make a clean cut and indisputably end the connection. That's a fear I kind of suggest everyone to confront at least once in their lives, if for no reason other than to see what you're made of and what you really need vs want. Like Sartre said, "if you're lonely when you're alone, you're in bad company". Wish he had also waxed philosophical about one-sided relationships but that's up for us to decide as individuals :( Good luck with how it works out!