I'm getting a little discouraged.

I'm getting a little discouraged. I love playing in survival mode, but the one time I was able to spend enough time in this world to get the resources I need to make maps and armor, I died and lost it all. I'm used to coming back from that, but the backup maps that I've made haven't been working. When I take a map off the wall to make a copy, the map disappears. It looked like it went into my inventory, but it wasn't there, and didn't show up anywhere around. (Sometimes a map will appear in a nearby room when it's taken off a wall.)