only once, but i was an an adult in my professional phase of life.
i was working a very swanky practice in the area was we were growing faster than we thought. I was in line for a partnership, and things were moving forward...until the practice appraisal came back. to make a very long story short, the owner did not think the appraisal was enough for his practice, and increased the amount considerably, (6 figures considerably). we started to have "discussions" about that number, and it got uncomfortable. the owner had a very nice lifestyle, and was getting himself into debt...especially with the IRS. the consultant who appraised the practice actually called me one night and told me i'd be paying his debt, and not to do it. this is unusual because they're supposed to be an impartial party.
it was the wednesday before thanksgiving, and i got a call from the owner. i was done. he didn't like how our discussions were going, so they were over and i was out of a job. i went from being inches away from a partner to having nothing. on top of that, i didn't want to tell anyone because my brother and his wife were announcing they were pregnant with the first grandchild in our family, and i didn't want to take away from it. it's been the only time in my life that i've been in a deep depression.