Should I quit my job and move so I can take care of my mother?

My mother is 82 years old. We recently learned that she is in Atrial Fibrillation and has a blood clot in her heart. She has started all the necessary medications but suddenly she is very short winded and has very little strength. (Her doctor said she has congestive heart failure now.) Her memory and interest in life are very good, but I noticed her legs are swollen and her nails were a blue gray color. My question is this, I am trying to decide if I should leave my home (I live alone)and career to be with her,(she lives alone too). My mother and I have always spent most of our time together, but now I am scared that time may be short and I have so many obligations on my time. At this point she doesn't require asistance - she very independant, but I keep feeling so scared that she might need me and I wouldn't be there for her.