London's Fire Chief has told Sky News she is having counselling because of the horrors she saw at the scene of the Grenfell Tower fire.
Dany Cotton said she still cannot sleep at night, three months on from the disaster which killed at least 80 people.
The capital's top firefighter said some of her colleagues who battled the blaze are having to take time off work to cope with the stress.
The Commissioner, the first woman in the top job, says she could not believe her eyes when she first turned up at the scene.
She said it looked like a disaster film and she found herself asking "how on earth could that happen?"
Ms Cotton, who was in the tower with her crews as it burned, says they could have done nothing more to save lives, such was the fury of the blaze.
In an exclusive interview, the commissioner addressed criticism at the time that there was a lack of high ladders to tackle the flames.
She said the heat was so intense, they would have made no difference.
Ms Cotton told Sky News that not a day goes by without her thinking about what happened in north Kensington and not just when she is at work.
"I'm not sleeping brilliantly. Like a lot of people, there's a lot going on in my mind. The effects of what happened that night will stay with me forever.
"I'm not making any bones about the fact that I'm having counselling."
Her real focus is her staff and making sure they get all the help they need, she said.
Colleagues keep an eye on each other, looking for signs they are not coping.
The people who are "quiet and withdrawn", she said, are the real worry.
But the Commissioner is also concentrating on the future and wants the Government to reconsider a request from London mayor Sadiq Khan for £6m more in funding for the fire brigade in the wake of Grenfell.
"I really hope somebody is going to pay and recognise the fact that we need to be ready and prepared with the best equipment available," she said.
"Sadly I've not got a money tree stored in my office, or an endless budget, but there are new threats."
Dany Cotton hopes, as everyone does, that Grenfell Tower is a one off.
But with a string of terror attacks already this year in the capital and the possibility of more to come, the Commissioner does not want to be strapped for cash as the need for the fire service peaks in future.