What does lost your cookies mean?

"Lost your cookies" is an informal phrase that means "lost your composure" or "become very angry or upset." It is often used to describe someone who has reacted strongly, almost in a hysterical manner, to a situation. For instance, "Amy was so angry that she lost her cookies after the meeting over her raise ended." The phrase is typically used in a comedic way, and is not intended to be taken literally.