Just take a pause. Deep breath and slowly observe your own breathing pattern. Do you know when and why your breath is shallow, or what makes it speed up? Just being aware of your breath tends to slow it down.
Breathing through your nose, observe the inhalation and exhalation. Which happens faster? Which is longer? Don’t manipulate them. Just watch.
Being aware of your breath pattern is the first step. Yogic practice is futile and fruitless if you don’t breath correctly while getting in and out of the posture. Always remember, if you’re in middle of practicing a posture, you must inhale once you get in the center position and exhale when the body moves away from the center position. Exhale while going sideways or bending forward and inhale while bending backward.
Always remember that respiration is closely tied to the heart and the quality of your heart health directly affects the span of your life, therefore take a deep breath.