cold feet vs collywobbles

cold feet

noun
  • A feeling of nervousness or anxiousness causing one to reconsider a decision about an upcoming event. 

  • Used other than figuratively or idiomatically: see cold, feet. 

collywobbles

noun
  • Often preceded by the: anxiety, fear, uneasiness. 

  • Often preceded by the: a stomach ache or an upset stomach. 

How often have the words cold feet and collywobbles occurred in a corpus of books? (source: Google Ngram Viewer )