A good read from HBR- https://hbr.org/2014/11/how-to-handle-stress-in-the-moment

How to Handle Stress in the Moment

Do

• Identify what your physiological signs of stress are so you can work to alleviate the tension
• Counteract stressful situations by taking deep breaths
• Find someone whose judgment you trust who can listen and provide counsel

Don’t

• Forget the reason you feel stressed in the first place — you are being asked to do something important and you want to succeed
• Let the negative voice in your head spiral out of control — talk to yourself in a logical, gentle tone
• Project your stress onto others — speak in a calm, controlled way and others will too