Shortness of breath- no travels, contact

On March 31st had feeling uneasy suffocation though feeling sleepy. When got up start went to balcony, though there was sufficient natural air out I suddenly started to have shortness of breath and then feeling weak, unable to stand and had feeling like going to collapse down. Had glass of hot water and then after 2-3 rounds got sweat and then everything was back normal.,..prior to this incident I had stuffy nose/running nose and while sneeze start to runny nose and then dry up. Also internally feel chills though no fever, no cough etc... visited a local physician and took ECG. ECG normal, bp, normal etc.However I tend to get chills within body in evenings though no fever, have shortness of breath, stuffy/nose. Also I am worried while going to sleep while in deep sleep if similar situation happen. Pls suggest. Currently after physician visit and meds: No running or stuffy nose, chills seems to subside. However while taking hot water bath feel slight shortness of breath. First incident