Small breadth. Come out of this problem?

I am on psychatric medicines for anxiety from past 2 years. I feel i have a very small breath, not only that i inhale and exhale simultaneously, the moment i try to inhale, exhalation starts simultaneously. I cannot do any pranayama or meditation because of this as i have to yawn i.e. open my mouth and take a deep breath from mouth. I have shown to ENT, he told you have no blockage in nose, this is because of stress. People think i m yawning while talking to them but all i m trying for is a deep breadth from mouth as i cannot take it from nose. I can do jal neti easily. There is no blockage. Only when i open my mouth big and breadth touches my throat and then I exhale it from my nose I feel comfortable. Will I ever come out of this problem?