Hello, 

As I mentioned in the title, I had played for about a week or so and then took a break for a couple of weeks.

Then, when I came back to resume a game that I had going, no save files were present including past games and all autosaves. Even my graphics settings were reverted.

There are no save files present in the folders containing files for the game.

Unfortunately, as I was not playing any games on my computer at the time, I'm not sure about anything that may have caused this regarding Steam.

I do however feel that this issue was brought on by something involving either Steam or the game itself; I have experienced no other loss of data.

Does anyone have any ideas as to what could have caused this and how I can prevent it in the future?

The loss of the saved game is not such a concern as my ability to save and return to past games in the future.

Thanks in advance for your reply.

Do you have Steam Cloud sync enabled?

If yes, could you please try disabling it for a while and check whether the savegames still disappear?