Suddenly no sound on playback

[melo3rd]

I've used Audacity for years and this has never happened.
-In the middle of playback in a project sound stopped playing, It was working for an hour before this and I didn't change any settings. It looks like its playing, the meters move and if I record something it leaves the blue wave imprint (I don't know the technical term). It looks like everything is working, just no sound what so ever. All other audio programs work, error sounds, internet sounds etc.

I've so far: changed I/O settings, restarted my computer, restarted the program, tried to record a new project file incase it was just the project file, even reinstalled the program, nothing.

I've looked through the forum and haven't seen anything like this but I hope its a common bug or something.
let me know, thank you.