> But what hit me back then was definitely not depression and/or anxiety. It was some mysterious illness that took me out for a week (kinda typical), but then made me unable to "breath normally" for literally months. It was innately a physical condition: unable to breath, unable to sleep well, unable to feel physically good for months at a time.

Sure. Pneumonia can easily cause that. It takes a long time to recover from it, even if you're young.

Fundamentally, "covid" is pneumonia caused by a particular virus, so it's not surprising that people (esp. people who had serious cases) might have similar kinds of lingering symptoms.