Fine, it may be a bad cold and you've felt unwell for a few days but it is not flu. Certainly not "a touch of the flu"
My dp has got flu at the moment and has spent the past almost week in bed, unable to get up for more than an hour and genuinely unable to do much. Having had it (thankfully only once) I felt like I was dying /might have been preferable.
Aibu to think people saying "I was unwell at the weekend, I had the flu" have NO idea how miserable it actually is?