I pressed save in the top left, but didn't realise I have to actually click save again and then commit to a location on the disk. I assumed that hitting save just overwrites the file you are working in.
This is how every other piece of document editing software works, so from a UI perspective, it would be counterintuitive to expect the user to do anything different.
Do you know when the temp file is held? Is there any chance for me to see my work again?