As I hand over my last tissue and she sinks down the side of the gym wall I feel like joining her. Years of training do not prepare you for this; no one provides you with the words to make this go away. "I'm no good, I'm a failure," she sobs, as mascara slowly puddles on her 16-year-old top lip.
"I got a D in my mock and Miss said I had to do better and that exam went worse... I'm a failure."
I work in a large inner-city comprehensive. As the head of science, I know the latest initiatives for turning 4 into 5, D into C and water into wine.
I make sure pupils are aware of the level they are working at and exactly what they have to do to reach the next level or grade. But I also know that many of my pupils come to school to be fed; I know many of my form group search for me in the morning for someone to say hello to, and I know that family stability on the estate where I teach is, in many cases, "fluid".
The problem lies in the fact that children have to jump through mythical golden hoops before they can be successful at something and reach the magical C or level 5. I'm the first to admit shamefacedly that there are underachieving pupils in my classes and that we need to target them, but what about those pupils who genuinely work their socks off, but whose best is a D or, God forbid, a level 4?
I dread certain times of year, when I'm standing in front of Set 8 giving out grades, or marking coursework. You have two choices: grin like a maniac and convince them that they will get through the golden hoop; or give up, tell them they won't make it, and hand out a word search. The first won't work because it's not fair to build up false hopes and your pupils know when you're bluffing. The second confines them to the reject bin at the grand old age of 11.
The second worst time of year just passed: sitting down with your department after the summer thinking of reasons for your "failure" as a teacher because Johnny got a D. But there isn't a box for the fact that Johnny broke his leg and lives with alcoholic parents who don't believe in uniform - or food, - and, actually, considering all of that, the lad should be proud because I know I'm fit to burst. The number of pupils I come across who say "I hate French, science, maths" is increasing. I know that the standard of teaching is not dropping and many teachers are turning cartwheels in classrooms to make lessons "fun". I suspect that, from a teenager's point of view, it's easier to hate a subject than admit you are failing.
But when did D become such a poor grade? I know a lot of colleges find this offensive letter perfectly acceptable. Surely somewhere along the line we need to teach pupils that all subjects are interesting and you don't have to be great at everything for life to be worthwhile. We need to stop this culture of stamping the foreheads of 11-year-olds with the word "failure".
Then they might just stop believing it too.
Sarah Murcott is head of science at Smiths Wood school, Birmingham