I'm really concerned about this shortness of breath I've been having for the past 10 days. My oxygen saturation is between 97 and 98, but I don't feel it when I'm walking quickly and I sleep just fine. I had mild COVID symptoms back in October 2020, and the shortness of breath was there until December, but everything's been alright for the past 3.5 months. I even got a CT scan through my pulmonologist, and everything seemed okay. But what's weird is if my mind is busy, I don't notice it, and if I try to take a deep breath on purpose, I just can't. What might be going on?