What does "coming out of my shell" mean?

Vocabulary Word: coming out of my shell

1. Definition (expr.) stop being withdrawn; open your heart and mind to life; stop being insecure; stop being shy; become more confident
Also:
become happier and less upset; change your mood from bad to good; stop thinking about your sadness and start thinking about positive things;
A good thought from Srikanth:
“The phrase brings to mind the tortoise: it goes into a shell when it feels insecure and comes out when it feels better.”

Examples “Mike used to be so shy. He was scared to talk to anybody. But now he always says “Hello” to me when I see him. Maybe he’s coming out of his shell.”

Examples “Jane was really sad after her mom died. She didn’t want to see anyone for months. But now she’s coming out of her shell. She’s feeling a lot better.”

Examples “When are you going to come out of your shell? You’ve been quiet and shy for too long. It’s time to start being the fun person you used to be!”