Sentence:  "My baby is a perfect bundle of nerves," said one mother to another. "She is so sensitive, she starts at the slightest sound. She sleeps only a few minutes at a time, and has to be walked or rocked to get her off again. She won't go to strangers, and I am a <WSD>nervous</WSD> wreck taking care of her." 
Meaning of the word marked with <WSD> tags:  Apprehensive, anxious, hesitant, worried.