- Become infected with some massive head/chest illness that makes you feel like you have been run over by a bulldozer.
- Wear only the rattiest pajamas you have because dammit they are your favorite, making you kind of look like you were run over by a bulldozer.
- Blow your nose so much that your face becomes raw and red and looks as if it will peel off any moment. (Don't forget the puffy eyes and coughing...a lot of coughing...even better if you're hacking stuff up.)
- Only have enough energy to wander around the house wrapped in a blanket groaning, "uuuuuuuuuugh."
If your significant other, looks you in the eye and says, "If you don't go to the doctor, I'm going to have to shoot you in the head just to be sure" then you have successfully become a zombie.
Be sure to thank your S.O. for being so thoughtful.
Or, give him/her your infection and go off together and create the zombie apocalypse that the interwebs wants so very badly and laugh your zombie asses off at all the blowhards who become food for the hoards.
That would be so romantic.
There's also the "If you loved me, you really would shoot me in the head." option. In my house, that is always followed with, "Ugh, and have to clean up all the blood? Ew." Lying bastard!