[Epistemic status: I am not a doctor. Things I've heard may be incomplete or out of date.]
If you think it might be COVID-19, get tested ASAP to make sure it's not just a cold. Talk to a doctor. We're well past the point where the hospitals were overwhelmed in the U.S. Treatments should be much easier to get now.
There are monoclonal antibody treatments with Emergency Use Authorization. Even mild cases of COVID-19 seem to cause lung and brain damage, so it's best to get treated as soon as possible, to prevent any more damage. Many have reported long-term effects from the disease.
The recommendation from the FLCCC is "up-to-date advice" (whether or not you believe them is of course up to you):
Early At Home Treatment Protocol
For adults > 18 years and >40 kg/90 lbsIvermectin24 mg – daily for 5 days In the setting of poor clinical response, advanced disease, or obesity, higher doses should be used (target 0.4–0.6 mg/kg)
Melatonin 6 mg at night for 5 days
Aspirin (ASA)80 mg/day (unless contraindicated)
Anti-septic mouth wash Three times daily (gargle do not swallow); if available
LessWrong has hosted a few posts that at least in part tell people what they should do upon getting COVID. That being said, they don't seem to have been updated since last March, and presumably more must be known now. The topic is newly relevant now that the delta variant is spreading in many locations, with vaccination rates being low in most countries.