Audio not working on playback

Hello! I'm working on a project for school right now and suddenly the audio in my animation file has stopped playing back when I preview the animation. I have a pretty heavy duty due date and I need the sound to work on the animation so I'm kind of freaking out, haha! Here's what I know:

I'm working on a Mac running Catalina. 

The audio HAS worked on this file before, I was working on this for the past couple days!

The audio file is already set to 'stream' and not 'event' -- scrubbing is not working currently either, however.

The audio file is 44 kHz Stereo 16 bit, so it's not a size issue -- plus again, this file has been working before.

No other audio files in other animate files are working either, so I don't just think the file is corrupted.

I've clicked into the audio settings for the specific file and when I click "test" I can hear it.

Does anyone know what to do? Did I press a button and mute my files by accident? Please help me :,( 

Thank you so much!!!