I agree with Elizabeth, take break and write more of your novel. And I agree with Paul, unlock your posts for a while. Get money out of the equation and see if that helps. I lock my posts, but I never count on making any money from Medium so it is all bonus. I know I can’t make a living writing what I write so I view it as a hobby with benefits.
When writing is no longer fun or rewarding, I will stop. I have plenty of other interests to take its place. I know this isn’t much help to a real writer, but that is how I view it.