How sad for you (both). I'm not sure I have any advice, but I read your post and felt for you. You sound as if you have had a long and generally happy relationship with her?
If you think hard about it, is there a point in time that things began to change? Did that co inside with her change of mood? Which leads me on to wonder if she is ill in some way?
Or perhaps some change in your life has caused her to think about the relationship in a different way?
I feel so awful, I've sat with my friend for hours sat in hospital with her for hours, but I feel like I can't cope anymore. I went to the cinema with her and had to leave after the film. She was just so nasty and cutting with me. I really miss her and how she used to be. I also must admit I've been a bit scared of her too. I just don't know what to do