I;m really bummed over cancer with my sister Dianne?

I know it's going top get worse but gee. it heartbreaking. Dianne is doing worse. Hospice is with her all the way. She laste longer than expected but I cry every day knoiwing her time is limited. I need help and comfort. I don't want her die. She's a yr,younger than I am and Ihanve to wonder, am I m I next? This is our goden years. Our longevity died with mom at 96 To many of have died before 70. Is it fair. I have to wonder. I need comfort and words of wisdom. someone please help