I'm sorry for your situation.
Has your relationship with her always been like that? I myself would sadly be on the other end where your daughter is, where I'm the part trying to reach out, so I in some ways can relate.
I would therefore like to emphasize that it's important to step lightly when things are so imbalanced and wobbly. What exactly are you feeling guilty about? And what, if you so wish to explain further, is the reason for her to act like this?
The worst case scenario here is that your relationship with your daughter would get worse, that you or she would move further away and this huge gap would form between you.
Do you have any clues as to what went wrong or where it went wrong? Figuring out what's the cause of the distancing is key, because without it, you'd only be making guesses and asking the wrong questions.
Hugs and love.