Pay attention to your breathing for it is a marker of health and emotions. The breath is the link between the symptomatic and the asymptomatic nervous system, between the automatic and the manual functions of the vessel. The only action that can be consciously overridden. The less breathes needed over the same time, indicates a more efficient body system. Shallow breathing that is faster can trigger nervous responses for emotions that the vessel is yet to feel and as such we can trigger stress states and feelings merely from how we control our breath in the everyday. Slower breathes such as those taken in peaceful states, will bring a physiological level of calm to the breather just the same as faster and shallow breathes bring the physiological level of stress. Begin to take deeper breathes with the diaphragm expanding the stomach and breathe through the nose.
Meditate.