When to Say "When"

I've made the difficult decision this week to resign from my church post. Having been the church secretary for five years, I've been there longer than the pastor. When the church had no pastor, I was there every day, week after week, for several months doing my job, publishing a weekly bulletin and a monthly newsletter.
Last Thursday I was ambushed at a job evaluation. I sat down with the church pastor and our Staff-Parish Relations chair and was completely flattened by what they had to say.
I think I am pretty realistic about my limitations. I filled out a form pertaining to my performance. I didn't give myself all "excellent" marks. I jotted down areas where improvements could be made.
The next thing I know I'm being assaulted with what a terrible job I'm doing. Funny thing is, I work two part time jobs. I give equal effort to both positions. At my afternoon receptionist job (that I've had for 5 months) I've received two raises, invitations to office functions and lots of praise. The afternoon job is much more hectic and complicated. How can I be perceived so differently?
Well, I guess I really can't be. The folks in the afternoon have wanted me to come on 3/4 time for quite awhile and I'm going to take them up on it. I don't need the aggravation.
You should NEVER be surprised at a job evaluation. If that happens, it means that your manager/boss has not been communicating with you. As problems come up, you should be hearing about them.
This didn't happen to me. I take pride in the job I do. I cried. I wrote a letter of resignation. (Did I mention that it's been 4 years since the church gave me a raise?)
I'd love to hear from others that had this happen to them. Cry on my shoulder. Tell me what you did. Share with me your cleverly worded resignation letters or speeches. I'm waiting!