Simply put, the day before yesterday, or two days ago.
Dude 1: "Hey man, did you see that new episode of Jersey Shore? GTL, amirite?
Dude 2: GTFO, that was so last yesterday.
Means earlier today. Most offten used by Nancys that have been hanging around Bulgarian guys too long and have become thier pimp.
You know what happend last yesterday when Georgi came in to work this morning?