We use this expression to tell someone to stop worrying about something and control themselves. It’s often a reply in a moment of panic.
You can use this phrase in ………… language.
A: I’m so worried, it’s going to be a disaster!
B: It’s only cards. Get a grip!
A: I’ve got an audit at work, I haven’t had time to prepare for it. I’ll be fired!
B: Get a grip! The audit is next week, you should be able to do something about it.