For some reason my quick save has stopped working. Anyone know a way to turn it back on?

Quick save or auto save? (quick save is still a manual save, just you have to press a button or click it in the save window menu). Maybe you changed the keybinding and set it to another command. Check keybindings.

If you mean autosaves, go check your settings (options menu) and see what ones are ticked.

Quicksaves. The button push.

Check keybindings.

Thank you, guys. It turned out to be a false alarm ... my keyboard was dying. :/