 Lyrically , " Not Myself Tonight " talks about Aguilera adopting a new persona and new musical experiments . At the beginning , Aguilera admits that " Tonight I 'm feeling a little out of control " . At the pre @-@ chorus , she sings " The old me 's gone and I feel brand new , and if you don 't like it , fuck you " , which takes aim at anyone who dismisses her new style ; meanwhile , she declares her musical departure from her previous 1940s and 1950s inspired album Back to Basics ( 2006 ) at the chorus with the line , " I 'm not myself tonight , tonight I 'm not the same girl " . The song also evokes sexual theme , with lyrics such as " I 'm dancin ' a lot , I 'm takin ' shots and I 'm feelin ' fine / I 'm <unk> ' all the boys and girls " . Writing for Billboard magazine , Michael Menachem opined that Aguilera channeled a " more ' Euro @-@ glamorous ' version " of her previous alter ego " Xtina " , featured in her 2002 hit " Dirrty " from Stripped . 
