No Achievements Unlocking 1/14/15

I played Halo: MCC last nigh and should have received achievements for completing the last two levels of Halo 2, completing Halo 2 on Heroic (Normal & Easy), completing the first 2 stages of Halo 3 and finding 4 skulls. Not a single one of these achievements unlocked. Do I now have to go back and do them all again?