Yeah that happens when you least expect it. You may be a professional but you are only human and you had/have unresolved pain. They, being professionals, should understand this so don't feel too bad.
Until you deal with this correctly, it will happen again when you least expect it. At first I used it as a barometer to the person I told my "secrets" to see if they were worthy, depending on how they took it. If they were appalled and used it against me, better to know now than later. I have become much more in control and judicious as to who and when I tell these things now. It will come.