I Am 23 And Male. For The Past 5 Days

I am 23 and male. For the past 5 days I have been experiencing shortness of breath consistently. My blood oxygen level was 95% and my lungs are clear (a doctor checked those by listening to my breathing and a blood oxygen finger test) but last night i couldn't sleep because I was struggling . It is definitely not anxiety but it is starting to worry me. Is there any reason this could be happening