Why did the author say: “Your head is missing,”?

Directions: Read the passage and answer the question that follows.

“What’s wrong?” asked my customer as I covered one eye, then the other, and stared at her in disbelief. “Your head is missing,” I said anxiously. I slumped on the stool behind the counter of my fashion boutique and placed my palm over my left eye. Sure enough, there was a large black area at the top of my vision in my right eye.
A phone call to an ophthalmologist’s office started the ball rolling and a dye test to look at the retina was performed that afternoon. That night I couldn’t sleep with worry, petrified that I might go blind. The eye specialist confirmed that there was damage to the retina and he wasn’t sure exactly what the cause was – a virus, perhaps? He stressed that it could happen again and cautioned me to keep my immune system strong. I was given a dose of antibiotics and told to rest.
That was in 1986. I was 36 years old, married with three children and working full time. While it didn’t take long for me to grow accustomed to my vision impairment, the shock of partially losing my sight made me rethink my life, and I left my marriage of 19 years. Moving to northern New South Wales in 1990 gave me the chance to experience living in a small community. Perhaps it was the pressure of a new job, a new relationship, and raising a family that took their toll, but by 1993 the vision in my right eye had become more cloudy and blurry. The specialist asked me if I’d ever been to the Wheat Belt in America, as the scars in my retina were similar to a disease from that area. I hadn’t, and so we remained in the dark about what was causing my loss of vision. But I did notice that I was often tired and found it an effort to keep my head upright. I wanted to sleep all the time.