If possible, try to learn breathing exercises. It's what has helped me. When I first had symptoms, I spent a few days fighting the urge to take a deep breath whenever possible and over time it lessened the sense of need of having to take deep breaths. Breathing exercises, particular the Buteyko Breathing Method combined with light to moderate weight lifting is what helps me manage symptoms. I think the weight load on my muscles with controlled breathing increases blood oxygen and vasodilation which helps with breathing. The Buteyko method helps me to breathe less and thus my body doesn't expect deep breaths as much, lessening the feeling of air hunger.