Survivor's guilt

Today I woke up experiencing what I can only call survivor's guilt. L. may already be dead; dying E. will leave two very young children; P. passed away weeks before her life goal of seeing her son graduate high school; D. wasn't prepared for a poor surgical outcome, never bounced back from anesthetic and didn't have a chance to say goodbye. Why am I still here?

I didn't do anything to deserve cancer, yet I got it. I developed a life-threatening post-surgical infection. I got through chemo and radiation. Then the cancer came back worse than the first time. I broke my leg, was convinced i was dying. Yet here I am, four and a half years later, with limited mobility but truly excellent quality of life, still stable on estrogen blockers.

What's different about me? Or is it all random?