I think it might be an advantage to get GI symptoms first, so you start making antibodies before it gets in your lungs. Just a theory. It could also be that people on high-dose Vitamin D daily don't get very severe lung infections from Covid-19. High D versus insufficient D (<25) yields a 70% protective effect against respiratory tract infections. This is based on a peer-reviewed British medical journal paper analyzing multiple good double blind studies with a total N of over 10,000 patients. This is the real thing folks, not tabloid or Vitamin nut propaganda.

When you do get lung symptoms, it's very good to have a pulse oximeter available. They sold a few weeks ago on Amazon for $15-$20, but they may not have any left. If your SpO2 drops below 90, you are in trouble. If it gets much lower and is heading down, you need oxygen. Call your medical group's nurse or covid hotline and tell them your pO2 to ask for instructions.