WordPress 3.8.1
Woocommerce 2.1.2
I’m also running a theme built from scratch by some very cheap overseas web designers which was later heavily modified by me, so a number of things could be causing compatibility issues within the theme itself.
I seemed to have fixed it though. All I did was deactivate the plugin and then reactivate it. No data was lost and everything seems to be working again.
It seems like it might be a temporary fix though. I’d still like to know what exactly was causing it if anyone here knows anything about the issue.