The phrase "tied up in knots" is often used to describe someone who is feeling stressed or uncertain. Synonyms for this phrase include "in a tangle", "in a twist", "in knots", "in a predicament", "in a jam", "in a bind", or "in a maze". These synonyms imply a sense of being stuck or trapped in a difficult situation. Other phrases that convey a similar sentiment include "on edge", "nervous wreck", "anxious", "upset stomach", and "butterflies in the stomach". These phrases all suggest a feeling of discomfort or unease that can be caused by a range of different situations.