Session expired, campaign erased... lost several hours of work... WTF?!

I put several of hours into what I was working on and had somewhere to go unexpectedly. I came back to my computer only to get the "Your session has expired message" followed by a refresh that cleared everything I had worked on. I have no clue if there's any way to recover what I was working on... and if there isn't, then f*** this app, that's s****y.

I apologize for this, it should not have happened. Was there a red box in the top left corner? If you were not connected what you were working on would not have been recorded.  What is the campaign name? The Devs can take a look. Also, when did you last work on it?  - Gauss

Campaign was named something like "DBZ CCG Sealed Draw".

I don't remember seeing any connection message or anything. I was working on it, it was functioning. I had like 9 decks made and was in the middle of a test game when I left for roughly 3 hours and came back to this "Your session has expired" message that also said something like "Click this to return to your campaign". When I clicked it, it rejoined the campaign as a completely clean slate. It's 9:00 PM now. I'd say that I was last working on it between 4 and 5 PM.