If the anxiety is caused by intrusive thoughts or a stressful situation, Box Breathing can help.

There's another technique where you name five things you see; four things you hear; three things you feel; two things you smell; one thing you taste. Something like that. I don't know what it's called or if I've got it right. Maybe someone else confirm? The general idea is to engage all your senses to "get yourself out of your head" and be present in the moment.

Good luck! You can do this!