Memories to last a lifetime...hard drive, EPIC FAIL!

I never thought it would be me. I mean, why would it happen to me? I'm smart and so is my husband. We may not be computer nerds, but we are savvy with techs and gadgets. Just remember, it could happen to you too!
Hubby and I decided it was time to get to know a Mac computer, so we purchased the MacBook Pro and with it some bells and whistles. Once home, he opened iTunes to updated our iPhones; I reminded him to plug the external hard drive into the computer since that's where all the songs are stored.
Oh boy, what happenned next it was complete and epic fail! The computer asked him if he wanted to convert it into the "Time Machine." Unknowingly he pressed "yes" or "continue" or "do it"...whatever! The point of the matter is...my little 500 GB hard drive with all of my songs and pictures was reprogrammed to Apple and in the process, erased all of my files. Yes...you read it right, erased ALL OF MY PICTURES!
The last two years of my life, gone! The time I spent editing all of my photos from my travels to Italy and D.C., gone!
I am a picture person, but I have come to the conclusion that a picture is just your visual memory, but in reality, we carry the best memories in our hearts. Treasure yours moments and make them into memories.
Lesson #2, have a back up for your back up...you never know when you will need it!!!