Have I overwritten my iphoto library without knowing?

So I have updated the latest iphoto and have latest OS update to start with. As I operate on a small laptop, often I have my iphoto libaray in another location, like an external hard drive. I attached my Cannon and uploaded photos to iphoto and I presume it created a new iphoto library with these. They are summer holidays with my 98-year-old grandmother and 4-year-old son, etc. Really important photos to me. So the photos took an hour to upload and they were all there within iphoto and categorised and everything.

I thought it would be a good idea to move the photos to the external drive but I could not for the life of me locate the iphoto library! In iphoto itself only these latest uploads were there (no other pictures from before). I looked everywhere, scanned the pictures file and all else. I did a Spotlight search and turned up nothing.

So then I shut down and restarted and funny I found an iphoto library in the pictures folder now, so I started up the iphoto with the control key and designated that library. However, it was an older library from earlier in the summer that had not appeared before but was now there... and did not include my latest photos I uploaded. So I did a Spotlight search for iphoto libraries again and it didn't even find the one I was using now!

Needless to say, there is no sign whatsoever of my latest photos. I am now fearful that they have been perhaps somehow overwritten by the other iphoto library? But they were there and saved and everything but it's like they never existed. Of course my pics were automatically erased from my camera. Don't even go there... of course I will not do that again.

Any ideas? I am really anxious to get my gran pics.