Facebook not showing CERTAIN notifications?

[Isabella]

It shows when someone posts something on my wall, but only like an hour later. But it wont show if anybody posts a comment after me, or after someone that commented my picture, or if someone commented back on a post i posted on someones wall, or if i got a picture/video comment. anything like that!
I never changed anything in my settings but when i checked everything is the way it should be, but still won't show up !

please let me know what to do to fix this, it's annoying seeing things like a month after it was there without ever knowing lol

plz & thank you!! =]

-Isabella

[HotAirBalloon]

http://www.facebook.com/notifications.php