I'm suffering from a lack of verbal self-defense

Today I had a doctor's appointment to get the results of some tests on my heart and lungs. We first had a BBQ at work and I was preoccupied waiting for time to leave for my appointment. A girl said from across the gazebo, "What's the matter, you sleeping over there or you just scared?"
I realized she was talking to me and I just didn't feel up to coming up with a comeback. But, I thought, I defended this b--ch when another girl was saying they should fire her ass because she's lazy, doesn't do her job, and had milked the student aide program for 10 years while she went to school and "worked" part time, taking long lunches to go to the mall, and leaving early every day. I had answered compassionately, "but she has twins, she needs the job."
I thought to myself, could she be jealous that I got a promotion recently? At least because of my promo I felt in a good place though i was feeling weak, tired, and worried about my test results. When I got to my doctor's she and the attending physician, both really nice and concerned young women who put me at ease told me that my CT scan was not normal so they had referred me to a lung specialist just to rule out anything serious developing in the future like cancer or tuberculosis. I was asked if I had been exposed to TB or smoked or where did I grow up or did I work in an asbestos environment. I don't smoke but I do work in a hospital. At any rate I have faith in my doctors and their proceeding cautiously and caringly. It makes me sad that I may be seriously ill just when I finally have become a "career woman" with a respectable promotion.