It sounds fairly influenza-like. How about body aches or extreme fatigue?

I don't have any secret home remedies to pass along. But that post nasal drip may have little to do with your nose. Viruses like influenza can attack the lining of your throat. The cells eventually start to split open, releasing fluid, and leaving your throat raw. That is what is probably causing your post nasal drip and triggering the cough, although if you're starting to get pneumonia, then fluid in your lungs may be causing you to cough, too.

Unfortunately, for bugs that evade/overwhelm your body's first line of defense, you'll just have to wait for your body to identify the bugs and then produce customized antibodies in enough numbers to beat back the invaders. Typically, that takes a week to ten days to happen, so hang in there a little longer.

Stay hydrated, especially to keep the mucous in your lungs thin so you can cough it up.

Take care!