//Judge, it makes a lot of difference to me. I am extremely vulnerable and have not had Covid yet. If it was Covid, I would probably have to get antivirals, and take far more precautions than if it was a cold. I know that I can survive a cold.//
If that's the case and you feel grotty enough to seek medical treatment, the doc will decide whether or not you need a Covid test. There are a multitude of respiratory ailments that are just as dangerous (and some more so) than Covid. The decision for you is "do I feel ill enough to see a quack?" If you do, see a quack and let him or her decide what tests and treatment you should undergo.
With your vulnerability you would be most unwise to self-diagnose, especially with the relative unreliability of "amateur" Covid tests. I don't really understand why you "major" on Covid when there are so many other debilitating conditions about.