Yes. I'm definitely in that zone right now. Publishers rejecting me one-by-one, my dreams of a series with my lovable MC starting to spiral. Now I'm trying to get up the courage to try something a little different, kind of a mystery but not, first person and far more informal in tone that what I've done before. That's taking courage that I usually have, but that's only coming in occasional waves right now.
Aren't you an agented and published author? With an ongoing series and a true crime book under your belt (I thought you were). When my publisher said "No" to a new series I was working on, I simply promised them that I would continue with the series they were publishing IF they would take a chance on at least the first book of the new series. They wouldn't so I found a new publisher for series #2, with my original publisher's blessing (and some contractual negotiation and repeated promises to keep to the deadlines for series #1) since it was their decision. That's what I might suggest for you since you seem to be in a similar pickle.