It's that time of year, you're surrounded by sick people.
Parents tell you their child hasn't been able to shake off that nasty flu for over a week. A colleague comes to work looking worse for wear, she doesn't take off her scarf or her gloves all day, and you can tell she is shivering.
And this morning, you feel odd. You have a dry chesty cough. You almost feel you have a cold or a fever but not quite.
Is there an idiom or phrase that means you are getting sick? I don't want to say I am ill, or I have the flu over the phone because you can't tell by my voice, but I'm definitely feeling "off".
I'm sorry I can't come for dinner tonight because ________