M3 Perfect (slot 2, miniSD) problems! Help needed!!! Really weird and confusing!

I lost some of my save data earlier today.
Gone.
Poof.

I started a game again, played for an hour or so and saved. Quit and turned off. Checked to see if saved, it did.
Started 30 minutes later, gone.

It seems that all of my recently played games (phoenix wright: ace attorney, drawn to life, mysims and metroid prime hunters) have lost their data and keep losing it. They are all recently downloaded (except for metroid, which is quite old) but not all new roms (pheonix wright is in the 100's, and metroid isn't that recent) but the rest are unharmed (those of which I havn't played for a while).

It is the first problem I have had, and happened first after I saved a quit phoenix wright: ace attorney

I need some help please


*next day*
Still looking for help...