Uncertain diagnosis

Hi;

I had a bad dose of something flu like in December 2020 accompanied by dreadful cough which I couldn't shake off. On one occasion I coughed up blood. I recovered and started running up to 15 km a week in the spring My problémy began when I woke up one morning in April short of breath. With covid about it was very worrying but I didn't have any other symptoms but was never tested. I went to my GP he listened to my; chest, SP02 blood pressure, all fine and chest X ray good, he thought it was anxiety and prescribed sertroline. I also completed a peak flow meter test over a month and this was also good and had bloods and ECG all good. I still have SOB but the condition has improved over the last 9 months. I used to find I'd get breathless climbing stairs or talking on the phone, not gasping but just this low level sensation of not getting enough air in. On occasion I'd wake gasping and my heart belting and sometimes I'd wake with a headache. Now I can walk cycle carry my daughter on my shoulders for long distances without being out of breath gasping. I have no cough or sputum or wheezing either. I test my SPO2 frequently which is fine The biggest problem I have is with sleeping where I struggle to nod off as my breathing gets too shallow and it wakes me up. I find it all very confusing and contradictory because sometimes I can sleep for 5 or 6 hours without waking but when I do wake I struggle to get back off again. I don't understand how, if a lung condition prevents me from sleeping due to low oxygen that am I able to sleep at all. It doesn't make sense. I've been referred to a pulmonologist for a spirometry LFT but due to the pandemic everything is delayed. I'm terrified I have emphysema my self diagnosis suggests it could be and this heaps on anxiety. I have so many questions and no concrete answers.