Man Flu

I've been lucky enough not to have any flu like symptoms for over 2 years, up until today.
I'm feeling dreadful and am 100% sure that I got it from the coughing/sneezing mob in the office.

How do you fight this evil virus, apart from HTFU etc. my medicine of choice used to be Sinutab™ but has the side effect that I can't sleep properly whenever I take it.

And what's the general rule, if you've got the flu do you go to work (can't afford to take unpaid 3 days sick leave) or do you carry on working as usual and hope it goes away before/during the weekend?

I only take days off work when I am actually incapable of doing my job which is almost never.