M.B.
You should get to the doctor ASAP. I was just diagnosed with pneumonia last Thursday - if yours came on after a cold/flu then it's likely walking pneumonia. Mine came on suddenly - I thought it was bronchitis, but really had no cold or flu-like symptoms prior although I've been dealing with allergies. I was fortunate I had a regular follow-up appt with the doctor. My younger son also has it.
Just as an FYI, the flu is never the cause of death during these outbreaks - it is things like the secondary pneumonia, so this isn't something to ignore and hope it will go away. I was not even coughing and my only symptom was the tightness in the upper chest and fatigue and yellow mucous.
Also, pneumonia can be caused by bacteria, viruses or fungi. I have all 3. So, if you do get on abx, it is very possible for a fungal infection to develop. So, if you get abx, make sure you take probiotics (at least two hours away from abx) and you may need an Rx anti-fungal after the abx. The doctor Rxed those for both myself and my son.
Also, if abx aren't working within the first 3-4 days, you may need a different one - different types of abx are more effective against specific types of bacteria - I just switched mine yesterday.
Again, get to a doctor ASAP - the immediate care clinics like Primacare are a good option if you can't get into your PCP today. They are all very busy with this stuff.