"Butterflies in my stomach"

Amir46 asked about the meaning of "I've got butterflies in my stomach."

"To get/have butterflies in your stomach" is an idiomatic expression that means you are anxious and have a nervous feeling in your stomach.

Here's an example:

• I used to get butterflies in my stomach before school tests.

Sometimes the stomach isn't mentioned, as in this example sentence from Merriam-Webster's Learner's Dictionary:

• Even experienced musicians sometimes get butterflies before a performance.