Wtf why isnt my xbox 360 showing my achievements now?

alright so i went to my moms for the weekend and i got la noire and i got a whole bunch of achievements while over there btw the whole time i was over there i wasbt signed in to xbox live. then when i came back to my dads today with my 360 and my achievements werent there like wtf man 360 is gay i knew i shouldve kept my ps3. i signed in to xbox live and recovered gamertag to try to get my achievements back but no achievements still. so gayyyy