Every depressive is different when it comes to crying “Uncle,” and calling the doc.
My guardian angel Ann says that if she stays in bed three days in a row, she will call the doctor on the fourth day (or maybe the afternoon of the third day).
In my mood/sleep journal, I record my symptoms (lack of appetite, a pretty major thing in my world, difficulty sleeping, crying spells, difficulty concentrating, inability to make a decision, lack of interest in hobbies and work, and definitely suicidal thoughts). If they persist for a week (with intensity), I’ll call my doctor.

I called her yesterday because Eric could tell that life had gone out of my face. And he was somewhat concerned. When someone else tells me that I’m depressed, it’s definitely time to call.
Sometimes I experience very physical symptoms. The year of my breakdown I came down with six urinary tract infections (and it wasn’t because of all the sex I was having). My immune system was shot, and I couldn’t fight off basic bacteria and viruses. I was obviously run down and needed rest.
But it’s usually not that obvious. Like a detective, I have to list the clues (triggers), the symptoms, and work with a COMPETENT doctor at getting healthy again.