Dear Sara,
So sorry to hear about all your losses, and of course, your best friend being ill now. I have no words except to believe in yourself and the love for her as well as those who have already passed on. There are no words, actually to express to someone like you except, know you are in my thoughts and prayers.
Do all you can to help your friend, but do not neglect yourself. Eat right and get a lot of rest and know that God is with you, although I understand if you don't feel that right now. I don't believe God gives us these awful things to bear in our lives. I do believe God is our partner in all aspects of our lives and that he only wants us to live long and prosperous lives. I will not preach, just am lending out a hand for you to hold. Find some folks who do love you and allow them to embrace you with love and friendship to help you get through these trying times.
I wish you the best, always, sincerely, Angie