I hope my personal testimony helps you (and others). Years ago, I get tired easily, feeling depressed too. A blood test showed low count of white blood cells. My nutritionist at the time, a very up-to-date professional, requested a specific blood test for Vitamin D. Which was really low because I never sunbathe in sufficient quantity. She prescribed three 7,000UI pills a week and I never felt tired again. After 3 months she asked me to keep getting the suplemment "for life" (or getting more sunbath time). You can take Vitamin K2 to help absorb better the Vitamin D.

So I researched on the Internet about "Terrain Theory", which argues that we don't need a vaccine, but to keep our immune system always up to date. Meaning, a diet with anti-inflammatory foods (turmeric, ginger, red pepper, low carbohydrate to mention some, research for anti-inflammatory food) and vitamin D supplement. BTW, the diseases that kill most are caused by inflammation caused by excess of carbohydrate.

Also, if you have black skin, Vitamin D becomes more imperative because black skin cannot absorb enough Vitamin D from the Sun.

If his primary won’t prescribe the necessary meds to combat corona have him give look into this. I personally know two people who caught it, ER sent them home to take over the counter meds. They got in touch with this organization after receiving the proper cocktail they were better in two days.

https://www.americasfrontlinedoctors.com/how-do-i-get-covid-19-medication/

Oil of oregano is a natural antibiotic, antiviral, anti-parasitic & anti-fungal. I use Nature's Answer Softgels.

Please take 2000 - 4000mg of vit C (when you suspect you might need it) and otherwise 1000mg daily.

Please also take 10000 IU of D and start taking 5000 IU daily with K2 as suggested.

I’m not an expert but it is my understanding Vitamin D alone is a lot harder for the body to absorb. You need to add another vitamin with it to act as a carrier. My doctor has me take vitamin and calcium together during the winter. I’m a female so I’m not sure if that is why since women seem to have issues with both vitamins.