You had both your work and home computer logged into Elements? That's a recipe for disaster.
Elements saves your MOST RECENT session of play; because it last saved on your home computer, which did not have the cards you bought while you were at work, you lost everything you did while you were at work.
The save system in Elements isn't 'dynamic' per se. While you can play on one computer, leave it alone on said computer for several hours, and come back to it like everything was normal, you can't do it with multiple computers.