tie (someone or oneself) (up) into knots
1. To make someone oneself feel particularly confused, anxious, worried, or upset. I've been planning to propose to James on Sunday, but the nervousness is tying me into knots! Now don't go tying yourself in knots over the details of your papers—at this point, all you need is a cohesive outline.
2. To cause someone or oneself to become flustered while attempting to explain something. Jim's a smart guy, but for some reason he always ties himself up into knots whenever I ask him to explain something on the computer for me. The complex technical language kept tying me in knots as I tried to present it to the board.
tie into knots
Confuse, upset, or bewilder, as in He tied himself into knots when he tried to explain how the engine works. This metaphoric idiom transfers a knotted tangle to mental confusion. [Late 1800s]
tie somebody/yourself (up) in ˈknots
become or make somebody very confused: The interviewer tied the Prime Minister up in knots. He looked a complete fool.He tied himself up in knots when he tried to explain why he had lipstick on his face.