Sorry to hear that
I've been getting so scared of this happening lately with all the stories, every time I reset for whatever reason (for example, today when I was going to play my mayor I accidentally clicked new save file- and without thinking I immediately hit the power button...and another time when I was going on but meant to change the date on the game and instead clicked "lets begin" or w/e and it said "saving....do not hit power button" but I did it anyways T_T)
It seems a little silly that you can't back the game up....I've put waaaay too much time into this game. I have a second town and most of the time don't even like playing it because I don't have all the stores etc, I could only imagine if I had to restart my main town from scratch. I would probably just stop playing honestly