Okay, how about these for motivational blurbs:
1. Call in sick. Unlike "Keep your chin up," hearing this advice might actually make you smile.
2. Just get through today. Far more realistic a goal than "conquering" the day.
3. Puke and rally! Let's be honest, it's the best you can hope for.
4. Cover your mouth, jackass. Because nobody wants to envy you ... they just don't want to catch whatever knocked you on your ass.
5. Fuck you, flu! I realize this one comes with a host of censorship problems, but it expresses everything so completely.
6. Feeling sucky? Suck on this. This could also be dirty, even dirtier than "You got it in you." But it's more relevant to the product in particular. In fact, I think it should be the company's new slogan. I would buy cough drops with an attitude.
Your move, Halls.