In fact, recently, I have also encountered this similar phone data loss problem and learned a lot by reading many threads and articles.
In fact, my phone is just formatted by my brother and all wanted data is gone. However, fortunately, I have found a useful tutorial that tells about how to rescue data back from memory card:
How to Recover Deleted Files on Android
It is really useful for me and helps me restore all my precious photos with Android Data Recovery .
So, it may give you some clues, too.
You should learn to make data back all time, just like me.
