None of this is proven, or even likely to help much. Some of it may be worth a try if it doesn’t cause you significant side effects. Stomach pain is a good reason to say “never mind.” If you want a proven treatment for early-stage mild-to-moderate COVID-19 then a monoclonal antibody cocktail, such as Regeneron’s bamlanivimab, is an option. They are inconvenient to take, since they require an infusion.
Zinc *lozenges* (not capsules) might help shorten a normal cold, perhaps by reducing virus reproduction in the throat. SARS-CoV-2 is, essentially, a cold virus gone wild. The lozenges need to be started very early in the cold, so (since you’re probably 6 days in) it might not be worth bothering. Cold-Eez is a decent brand. Some have argued that citric acid inhibits the zinc’s action, so choose something other than orange or lemon-flavored lozenges. Here’s an article about the lack of helpfulness of high-dose zinc + Vitamin C: https://jamanetwork.com/journa...amp;utm_medium=email
Vitamin D is a mixed bag, very, very far from proven. There have been some positive reports and some (mostly better) reports suggesting that it’s useless. There’s a nice review here https://astralcodexten.substac...d-much-more-than-you
Most folks, even those at higher risk, will recover from COVID-19 and be fine. Some do very poorly, of course, and the overall effect on a community when transmission is out of control is terrible. It’s critical to isolate effectively so you don’t start additional transmission chains that infect enough people to cause numerous serious cases.
Good luck - I hope you feel better soon (if you’re having any symptoms at all).