If you're experiencing a sharp drop in the number of your listens, one major reason could be your podcast's listeners' concentration on one platform. When your podcast is heavily dependent on one platform, your listens can decrease drastically because podcasting platforms have a tendency to rotate the promotion of a podcast.
What can you do to fix it?
You cannot fix it immediately however to prevent this from happening again, you can distribute your podcast to many platforms to diversify your listenership source. It will help you find new listeners and might decrease your dependence on a single platform.
We also suggest including a message in your episodes encouraging your listeners to subscribe to your podcast to stay updated on new episodes.