I started with a faint sore throat & bit of a headache Christmas night, Boxing Day, nose running like a tap & headache getting worse. Today, didn't get out of bed until 10 & went back in afternoon for another few hours. Headache all through the night but couldn't drag my self out of bed to take Paracetamol. Feeling a bit better but don't really want to eat. Hope over next few days it's going to improve - hibernation is a good idea. I live on my own but plenty of food in so no need to go out. 
I'm on Anti-Histamines all year round, nasal spray & eye drops which seem to help.
I have had Pneumonia twice, once in the Summer (didn't even know I'd got it, anti-biotics cleared that). Last year I was in Hospital for 5 weeks with Pneumonia despite having the jab a few years earlier