I did start a new game.
Another weird thing, before I checked mission select and it said I had finished every mission on veteran.
I got out of the game, came here and then got back. Now, it says only the final mission was completed.
What the hell happened?
Oh, I hate you TREYARCH! I f@$#ucking hate you!!!
Now I have to return the game without my platinum even though I deserve it. Shit! Shit! Shit!!!!!!!!!