I will keep posting progress here.
Thanks for your help appreciated.
I am a 16 year old Female, not the healthiest but no different from many of my friends. My anxiety first began with breathing problems aswell. For me it has escaleted, uncontrollably. But just know that you are not alone. I have found that it is emmensely comphorting to know that there were others in the same boat. Judging by the tests you have already taken, and breathing problems being your only symptom of anxiety, there is nothing wrong with you. Anxiety is so common, most people just don't realize it because they usually deside to keep it to themselves and work through it on their own. All you need to do is stay active and live your life as you normally would. Anxiety will come about at the most random of times so you just need to come up with a regular action plan to use whenever your anxiety starts acting up. For me, writing, listening to music, or even going onto this site.
Above all, anxiety can get the best of you if you let it. So remember to always tell yourself that there is nothing wrong with you. :) I hope I helped even a little.
Feel better!