Well, taking root word (assuming nemesis), I would assume that it would be along the lines of revenge was just had.
ie, if "you've just been nemified", I would assume that someone just got revenge on you.
Definition for nemesis...
Main Entry: nem·e·sis
Pronunciation: \ˈne-mə-səs\
Function: noun
Etymology: Latin, from Greek
Date: 1561
1 capitalized : the Greek goddess of retributive justice
2 plural nem·e·ses \-ˌsēz\ a : one that inflicts retribution or vengeance b : a formidable and usually victorious rival or opponent
3 plural nem·eses a : an act or effect of retribution b : bane 2