DOE or dyspnea on exertion is usually a term you will see professionals use so wondering if you have a medical backgroud?
DOE also called shortness of breath (SOB) or air hunger, is a debilitating symptom that is the experience of unpleasant or uncomfortable respiratory sensations. It is a common symptom of numerous medical disorders, particularly those involving the cardiovascular and respiratory systems; dyspnea on exertion is the most common presenting complaint for people with respiratory impairment. With your GERD do you by any chance have asthma or breathing problems associated with that dx?
When shortness of breath is caused by anxiety, it may be because you are breathing incorrectly and therefore not taking in an adequate supply of oxygen. Deep breathing is needed to give your body the oxygen it needs. When you hyperventilate (take shallow breaths, breathing short, quick breaths), you are limiting the airflow to your lungs. This can contribute to shortness of breath.
A good place to start may be with a visit to your Dr. to rule out any medical reason for your dyspnea.