Xbox achievements wont show up please help?

Ive been playing two games today and have gotten achievements for both of them and when I go to see them it says that I dont have any and also that I havent even played a game. And it wont show my avatar and it shows no last played games and no gamer rateing. I have no idea why, but when I restart my xbox it will go back to normal. And as soon as I get another achievement it messes everything up again. Im going to call the xbox people tomorrow because its to late now but does anyone know what it might be the problem?