Some tips to help with breathing:
To calm to mind and activate your core, exhale as if blowing into a straw (with pursed lips). Inhale through your nose. Keep the breath soft and balanced between inhales and exhales. Practice for 1-2 minutes.
Abdominal breathing. Lie onto your back with bent knees, as you inhale, let your abdomen rise and as you exhale, feel your abdomen lower towards the floor. Practice for a 2-5 minutes.