This is a very personal story of mine.
When I get overwhelmed with anxiety I hold my breath for a few seconds.
Afterwards my lungs fill with air and new fresh thoughts.
A long exhale. My anxiety gradually goes away.
A new inhale. My mind fills with calmness and confidence.
Don't breath
Exhale.
Don't breath
Inhale.
Don't breath
Exhale.
And you are calm.