Unfortunately, I had to resort to disk formatting due to issues with windows keyblocker (still no idea why). When I try to load my world (saved on Google Drive as a .world file before formatting), CAW gives me an error message "unable to load file". CAW version matches my game version (1.67). I have no issues with creating new worlds and loading already installed worlds. There were no previous issues with the world file itself. I had not started The Sims 3 game yet - does it has to do something with this error?

Please help These are 2 years of my work. I am devastated.

Is that a world that was exported from CAW to install to the game? If so, then you need to unpack it to be read by CAW.
modthesims.info/showthread.php?t=469942
If it's an unpacked world that you saved from your CAW UsertoolData folder, then there needs to be the accompanying folder with the world resources (layers, lots etc., ) with it.