心慌 (xīn huāng): to be flustered; (dialect) irregular heart-beat

Before every exam, I get so flustered that I can't sleep.

When she first spoke on stage, she was so flustered that she couldn't speak clearly.

Hearing the bad news, he felt a sudden fluster and didn't know what to do.

The interviewer asked a difficult question, and he felt somewhat flustered, answering with hesitation.

Walking alone on a dark path, she became more and more flustered, and her steps grew faster and faster.