In fairness, I've taken 2 days off sick in the last 20 odd years.Crikey where I work it's almost mandatory that all non shopfloor workers hardly ever turn up for work. I've not seen some for 3 years. Yet they get "attendance" bonus and mysteriously are never,ever
The reason being is that I've always had the ability to work from home. If I've got a heavy cold, or an infection, or something that precludes me getting into an office, my work ethic says "Until I physically can't sit at my desk, I'm going to work". Earlier in the year, I had genuine flu. I don't mean a heavy cold. Even then, I was answering emails on my phone several times a day.
If you're not sure if you have flu or not, the question you should ask yourself is "Do I want to drink that glass of water? Will that mean I don't have to to crawl to the toilet?"
If the answer is No, then you probably have flu. If it's an inconvenience, you don't.
One of my biggest irritants though is office workers bringing in a cold. Phone your Manager and say "I know today is one of the days I'm supposed to be in, but I have a cold and can work from home". If I was your Manager, I'd be "Absolutely. Work from home. Get well soon"