A father of two who tweeted that he was "not OK" has said the outpouring of support he received after his post went viral has given him hope.
Edmund O'Leary said he was feeling "really depressed" after a "horrible year" when he posted his message.
His tweet on Friday night read: "I am not OK. Feeling rock bottom. Please take a few seconds to say hello if you see this tweet. Thank you."
Within minutes, he began receiving messages from around the world.
Since then, Mr O'Leary, from Epsom, Surrey, has been retweeted more than 14,000 times and received more than 300,000 likes.
He told BBC Breakfast: "The whole experience has been absolutely surreal and provides me with a lot of hope.
"I've gone from feeling like a nobody to feeling like a somebody.
"To have that happen overnight is just surreal, something that most ordinary people have never experienced or will never experience."
He added: "Eighteen and a half million people and counting have seen my tweet. Nothing can prepare you for that!"
When Edmund was feeling down he asked people to say hello on Twitter.— BBC Breakfast (@BBCBreakfast) October 19, 2020
He never imagined he would get the response he did 👏 pic.twitter.com/RjWkyJx9P5
It was a friend's tweets of a similar nature that inspired him to reach out to his followers.
"I was feeling very depressed, feeling rock bottom. I'm having an absolutely horrible year. I thought I'd give it a go," he said.
The many messages of support he has received include some from celebrities.
BBC correspondent Fergal Keane reminded him that "morning always comes" in a tweet with a recording of a poem by the late John O'Donohue which he had read on Radio 4's Today programme.
'You are not alone'
Meanwhile, CNN anchor Jake Tapper, who has 2.7m followers, also sent his support alongside a picture of two kittens.
He tweeted: "Edmund. I bought my mom two kittens after her beloved cat of 19 years died. Here's one of them, Lulu, playing. Things get better. They always do."
Mr O'Leary, an aviation enthusiast, said the first tweet he found "warm and loving" came from Dublin Airport.
Staff there told him: "You are not alone. So many people are feeling exactly that way at the minute. Never forget that you are loved & there are people who care about you."