That means that psychological stress factors and anxiety are causing you to hyperventilate (which you describe as the inability to take deep breaths,
and the incessant urge to keep
yawning). You think you are out of breath, and that you're nearly suffocating, and that only adds to the problem, and actually keeps you from attaining that "deep" fulfilling breath.
The usual medication would be an antidepressant and an anti-anxiety medication, like Deanxit.