Why didn't my game save on PS3?

So I played this game for literally five hours the other night on the PS3 and when I went to play today, my game isn't saved.

I'm back to level 2 and none of my friends or quests since then were saved.

I clicked to save the game after about an hour, and it asked me if I wanted to make a copy of my checkpoint, so I was like, okay, sure, it'll autosave too and it won't be a problem if I keep playing.
So the option to save after that was never available again.

I have no idea why, but I assumed it was autosaving whenever I was using the teleporter thing, because that's what it said online.

What did I do wrong and how can I make sure it saves my progress from now on?

Help help thanks.