Sentence examples for a sack of insecurity from inspiring English sources

The phrase "a sack of insecurity" is correct and usable in written English.
It can be used to describe someone who is overwhelmed by feelings of insecurity or self-doubt, often in a metaphorical sense.
Example: "Despite her many accomplishments, she often felt like a sack of insecurity, doubting her abilities and fearing failure."
Alternatives: "a bundle of nerves" or "a bag of self-doubt".