It had been about a week since I went on Streetpass, and I figured I would try to see what I had gotten (since I have all the DLC and stuff). Puzzle swap was missing all pieces, and all my progress was gone.
I panicked but then thought, "oh, maybe the SD card just wasnt in right."
So I turned off my system, took out the SD card. put it back in and booted the system back up. Luckly all my puzzles were back, and my Find Mii (2) progress was where it should have been. Unfortunatly all my other progress in Mii Force, Flower town, Warrior's way, and Monster Manor are all still non-exsistant. I'm afraid I will just lose everything again should I try to start over. I am very upset that one of my once favorite things to do after travelling was essentialy ruined. It will NEVER be the same again 
What might have caused this, and what can I do to make sure it NEVER happens again?