Lost everything on iPhoto. It's like I'm starting from scratch?

Question

Recently I upgraded to Yosemite.  I thought I had done an image back-up on from my iPhone on to iPhoto since, but I may not have.  Two nights ago I opened iPhoto to find everything had disappeared and I was seeing yellow sticky notes indicating that iPhoto had defaulted to it's original version?  I tried holding the option key while opening the app, but that only gave me the option to open the default library.  I tried to search for another iPhoto library in the finder, but nothing seems to be working.  I'm very sad to have lost many pictures of my children, please help!

Answer 1

If you check the checkbox next to  Camera Roll it automatically selects all of the photos in the roll.
Note:  even though the thumbnails don't show in the window for some of the photos all of the photos were recovered successfully.
The next step would be
Using iPhoto Library Manager  to Rebuild Your iPhoto Library
1 - download iPhoto Library Manager and launch.>Click on the Add Library button,
2 -  select the library you want to add from those in the selection window.
3 - make sure that in the rebuild window the checkbox  "Scavange orphaned photos" is checked.
4 - now that the library is listed in the left hand pane of iPLM, click on your library and go to the Library ➙ Rebuild Library menu option
5 - in the next  window name the new library and select the location you want it to be placed. Click on the Create button.
Note 1: This creates a new library based on the LIbraryData.xml file in the library and will recover Events, Albums, keywords, titles and comments. However, books, calendars, cards and slideshows will be lost.
Note 2:  Your current library will be left untouched for further attempts at a fix if so desired.