I think swapping hats can be really good for us, and that this may be especially true for teachers. Besides, isn't one reason for wanting to be a teacher a desire to learn?

It can be hard to stay confident in ourselves and our writing when we receive rejections, but I doubt this is really a matter of you not knowing what will sell, so much as your novel simply not finding the right publisher. I hope you are continuing to look for a home for it. Do you work with an agent, or have you been submitting it directly?

Good luck with all your writing projects.