Total Zombie Mode

Feeling completely dead, but having to live your daily life.
Feeling like the walking dead

Could mean feeling totally wasted, having a hangover or non-alcoholic hangover causing this feeling, etc.

Friend: how are you.

Pete: blehhhuhhh...umm.... *starts snoring then wakes up* uhmm, what did you say?

Friend: God man, you look dead. Someone's in total zombie mode huh?:

Pete: guess so man.