So sorry for your loss, Marky.

You know it is not your fault, yet it will always kind of feel like it is.

Though you could also consider that she may not have held on as long as she did were it not for you. Your friendship may have added years to her life. You'll never know for sure. You certainly added happiness to her life - for a time - and perhaps this experience has made you wiser and will help you know how to act with people who will need you in days to come.

My condolences.