what does "gut tightened a little"mean?
“Mr. Landon, this is Sherrilyn Burke, Burke-Massey Investigations.”
“Yeah.” His guts tightened a little, anticipation and dread. “It’s good to hear from you.”
“I have a report for you. I could e-mail it, but I’d like to go over it with you in person. I can come out to you tomorrow, if that’s convenient.”
“Is there something I should worry about?”