It’s actually a hat trick, if you can pull it off. You will get from 20-30,000 IU of Vitamin D from 15 minutes of sunlight on a lot of skin. However, there is a delay before it gets into your bloodstream of perhaps two days. So you get the sunlight, and *also* take 30,000 IU to close the gap, until the natural stuff kicks in. Importantly, you must find out if you have any sensitivity to Vitamin D first, as a few people react to the pill form with as little as 3,000 IU.
Unless you are in one of those places where it is mostly dark, cold and with little sun. It would be a very good idea to get a natural light sun lamp if you live there.
When you have a cold or the flu, several of your vitamins can become quickly depleted, not just Vitamin D. So it is good to take some Vitamin C, and a *normal* dose, *no more*, of Vitamin A, because you can most certainly take too much Vitamin A.
I would personally suggest having some Wheat Germ, as well, because it has some of the less common nutrients, such as Vitamin E, folate (folic acid), phosphorus, thiamine, zinc and magnesium, as well as essential fatty acids and fatty alcohols.
From there, the rules are different, depending on whether your infection is viral or bacterial. An URT and sinus bacterial infection often shows up in green or yellow mucous. In either case, be mentally ready to take it to a doctor if it suddenly becomes acute, you experience breathing problems, or you start to cough up blood.
If it is just a regular disease, you might drop down to 6,000 IU of Vitamin D a day, in two or three doses. Save the really big doses for when it is a dangerous disease, not just an annoying one.
Still tired, but no obvious cold symptoms this morning.
I'm considering getting one bottle of DHEA, just to see if it might "jump start" my internal engines, LOL.... yawn/yawn/yawn
My main concern, however, is as you note -- am I developing pneumonia or bronchitis via this malingering cold, and if so, when do I *have* to see a doc about it? I hate to go to the doctor's office when I'm under the weather, as who knows what all one might get infected with in the waiting rooms? LOL