If you are playing tournaments make sure you have downloaded both the hand histories and the summary files:
GGPoker Configuration GuideIf you have imported the hands check you have the correct player selected. Your name in GGPoker hand histories is 'Hero' regardless of your actual player name on the site:
Guide: Changing the Active PlayerMake sure you are in the correct section. Cash game data ($) and tournament data (T) are separated if you have imported only one type of data you would not see it in the other section.
Also check that you do not have any filters or tags that would prevent your data from appearing.