Is it morally wrong for an atheist to work for a business that is affiliated with a church?

For many years I had a job teaching at a private preschool that is a part of a Methodist church, and I really loved my job. Every now and then I would get the feeling that I did not really belong among my coworkers since most of them were devout Christians. They were very nice people though, and there was one agnostic coworker with whom I developed an especially positive, comfortable relationship. There was nothing in my job description that required me to perform tasks I felt uncomfortable with. I left because I wanted to try something new, and I liked the idea of not being associated with a church. I accepted a new job at an elementary school with no religious affiliation, and I have found myself missing my old job tremendously. I feel overwhelmed with a very large class and some stressful duties. I also have no lunch break during the day and end up working more hours than I am paid for. I also miss working with younger children; I think that age group was a better fit for me. I am feeling burnt out at my new job, and I have only been here 2 months. I have been considering the possibility of returning to my old school or seeking a position elsewhere at the end of this school year. If I were to ask about returning to my old job, should I have a talk with my boss and let her know that I am atheist? I feel like that might make me feel better, but then again I also feel that religion and politics are topics that should not be discussed in the workplace. Do you think it is wrong for an atheist to work at a church preschool?