be tied (up) in knots

To be confused, anxious, worried, or upset (about something). I've been tied up in knots trying to come up with a good topic for my term paper, but I just can't think of anything! James is tied in knots over how to break up with Danielle, but I think he needs to bite the bullet and just do it. I was tied up in knots waiting for the doctor to call with my test results. I'm so relieved they came back negative.