Photos Missing from iPhoto with Maverick Upgrade

I have recently upgraded to the Maverick OS and noticed that all my photos are now missing from iPhoto however I can see them under Preview when I use the Finder application. Also, when I open iPhoto it prompts me to enter personalized settings as if I am using it for the first time (ie: Face recognition, etc.) How can I get my photos back into iPhoto? I am worried I may lose them.