Agree if someone with “flu” makes it into work, then it isn’t flu. I’m 41 and have had flu twice in that time, both times it took me off my feet for a week on each occasion.
(And all the similar ones)
No, you don’t have Flu, as in influenza. Not even close. Flu will slay you. You won’t eat, move, think or do anything normal. You will ache, shiver, sweat, maybe throw up, be dizzy and every part of you will be affected. It will last for a long time 1wk at least.
In modern terms:
Flu = A cold. Maybe a bad one.
Chest infection = A cough. (People don’t seem to get coughs any more, it’s always a ‘chest infection’)