When you find yourself extremely stressed:

Be like Dog. Pretend to be perfectly calm and relaxed even when your thoughts are in disarray. In the same way that water assumes the shape of the vessel in which it is placed, your mind will begin to conform to the attitude of your body if you buy it some time.
Be like Hawk. Breathe, soar, and gain some distance. Take slow, deep breaths making sure that your airways remain open at all times. Make a conscious effort to hesitate for a few beats between inhaling and exhaling phases, but never hold or clamp down on your breath.
Be like your ancestors and go to the cave -- the cave of your mind. Regain your comfort zone by calling up a mental picture of either of a familiar and related training simulation or of an actual previous success during similar circumstances. You've been here before and you're going to be fine.
Be like Frog. Go on auto-pilot. Just be in the present moment.

Creature Teacher: Martial Arts Training Involution #176

These weekly T.I.s can be very physically demanding. This week we're going to take it a little break and do some head work. Practice the above drill. Run through all the steps one by one. Then make a note in your planner, or set a reminder on your phone, to run through them every day for the next week or so until you have them memorized. Then take a nice long sit, at least ten minutes. Try to practice your contemplation for double your usual daily length (but not more than an hour). Daily internal work -- contemplation, meditation and prayer -- are essential to the health of the human body, mind and spirit. If you're not doing daily internal work there's no way you're maximizing your health and potential. So get started!