When I looked back at the girl and the boy with the blue of the sky in my head, I saw that they were blue too. It was shining around them, out of them, as if there was a blue light inside each one. I stopped thinking about blue, and it stopped being there. I thought of it, and it was back.

Oh shit! I was losing it on an epic scale.

Ms Duke was going on in French, and they were a metre away from her. I spent a while making them go from blue to not-blue in my head, until they looked at each other, burst out laughing (silently) and ran out of the room.

This was happening all the time. It had started with the new girl in physics, who suddenly hadn’t been there any more. I’d asked Izzy, when I remembered, and she’d looked confused and had no idea what I’d been talking about.

‘There wasn’t a new girl in physics,’ she’d said, stroking my arm. ‘But you were in a bad place, and Mira did have different hair, so maybe it was that.’

I’d nodded and pretended to agree, but now I saw new people most days. I hadn’t mentioned them to Izzy again.

Mad wasn’t a nice word to use, so even internally I tried to rephrase it. This had to be me experiencing the onset of a mental-health crisis. But you were allowed to say anything you wanted about yourself, so I could say mad since I was self-diagnosing. Calling myself bad names was probably part of the condition, so it was OK. I am mad, I thought. A madwoman. Mad, mad, mad, mad, mad. I stabbed my pen into my book over and over again, perversely enjoying it, until I realized people were looking at me.

‘Sorry,’ I said to Madame D. I felt myself turning deep red.

‘En français?’ she said with a big smile to show she didn’t really mind.

‘Je suis désolée.’

She gave me a look that signalled, After the lesson? Ms Duke had a counselling qualification, and that was why she’d been looking out for me over the past year. Now she was supposed to report back if she thought I needed to go to a children’s home, so I really did have to remember to be less mad in her lessons.

‘Hey, Ariel,’ she said (in English, luckily). ‘So, what’s up?’

I’d spoken to her loads when Mum was ill, and it had actually helped.

All the same …

‘Sorry. I’m fine.’

‘You seemed to be miles away this afternoon, and at one point you looked very distressed.’

She must have been due for retirement, I thought. I hoped she had a nice plan lined up. I imagined her living on her own with a fluffy cat and maybe some geraniums.