Feeling of doom in some instances. i could be having a conversation at work and suddenly i feel having difficulty breathing, hard to swallow my phlegm. it is scaring me in some instances, since i dont know what to do. it constantly worries me, scary?

Feeling doom: 2 mandatory appointments needed. First, see your General Physician for a full physical examination including lab tests and possible imaging to assure that there are no physical anomalies or chemical imbalances. Ask your GP for a referral to your second appointment, this one with a health care professional. Your symptoms are not unique, and there is help available.