Hello and welcome to Healthcare Magic. Thanks for your query.
Firstly, if you are having no problem in breathing, then your lungs will automatically take in the adequate amount of oxygen
. You don't have to take any voluntary efforts or "extra deep breaths" to ensure that there is adequate oxygen.
Though you mention that you are don't think this is anxiety
related, this problem does appear to be psychological. Please remember, that anxiety can manifest itself with not only psychological symptoms, but with physical symptoms also. This physical manifestation of anxiety is called "somatic anxiety" and can be present even when there is no obvious psychological stress
I would advise you not to worry about this and breathe as usual, without any extra effort.
Wish you all the best.
Dr. Jonas Sundarakumar