Image credit: Karen Brocklebank/Letters for Noah

Noah Brocklebank's mother remembers the night she learned her 12-year-old son was planning to kill himself.

Karen Brocklebank said her son had been in therapy for long-standing depression and anxiety, but he was being bullied at Hammond Middle School in Columbia, Md., and he was feeling isolated.

In December, Noah cut himself.

"I had given him permission to get an Instagram account in December with the condition that I would stalk him on Instagram and that day, on January 26, I discovered that he had blocked me when I got phone calls from a couple of his friends," Brocklebank told ABCNews.com on Thursday night. "They were alarmed because … he had posted this picture of his arm all cut up and was talking about suicide."

Noah's note said: "Day of scheduled suicide, February 8th, 2013, my birthday."

"Immediately, of course, I was very alarmed," Brocklebank said.

She went to her son, made sure he was safe and calm, and talked with him.

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Noah was admitted to the hospital. While they were in the emergency room, he fell asleep but Brocklebank said she couldn't sleep.

"I was just so struck by how lonely he was, the pain that he was in and that he had put this proverbial cry for help out to his peers. That this was his way of screaming at this peers, 'I'm in pain. Look at me. Pay attention to me,' and I just wanted to take that away from him," she said.

She wrote to her friends and family on Facebook, and asked them to send him letters of encouragement for his birthday, the day he had planned to end his life.

She set up Letters for Noah, a special Facebook page, and got a post office box.

"My goal was to get 100 letters by that day. I thought I was crazy," she said.

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Within 24 hours, letters came pouring in. They came from classrooms, seniors groups and youth groups from across the country, and from well-wishers from around the world, and they haven't stopped.

On Noah's 13th birthday, the page was flooded with wishes for him, and supporters are still posting encouraging comments.

On Thursday, Facebook user Ed Ratliff posted: "Noah, people do care, and you have (touched) more lives than you know, stay strong. How many letters of support do you think those Bullies have gotten lately."

Michelle Langenbach added: "Dear Noah, I just dropped off a letter in the mail for you. Yes, us older people still use the snail mail option. :-) Stay Strong!"

Trudy Campbell of Ontario, Canada, wrote: "Hang tight kiddo… things will get better!!"

Brocklebank was stunned. She said Noah has been sent about 7,000 pieces of mail and at least 10,000 Facebook messages.

"It was unbelievable," she said. "I was really blown away by the response."

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Noah, an animal lover and sports fan who loves to sing, is doing much better. Even though he had the option of going to a different school, he chose to return to his school because he didn't want to start over somewhere new, his mother said.

"This whole thing has really empowered him and given him a voice," she said. "He's much stronger … still lots of ups and downs, but every week he's getting stronger.

"Things have really died down at school," she added. "There are still some things going on and he's really at the point now where it's not fazing him as much. He's really getting the message through these letters, I think, and also through his therapy, that he has to rise above it. And that this is a temporary thing; we have to take the high road."

Recent bullying-related suicides have led to a passionate debate about how to handle bullying in schools.

According to the U.S. Centers for Disease Control and Prevention in 2004, suicide was the third-leading cause of death among children, teens and young adults ages 10 to 24. In 2011, about 20 percent of high school students reported being bullied at school, and more than 30 percent said they were in a physical fight, also according to the CDC.

Brocklebank wants parents to talk to their children about being empathetic, but she also wants lawmakers to allow for stiffer penalties for children who are bullies.

"I'm not saying … if somebody is making fun of someone's hair that they need to be fined or sent to jail, but when it becomes so pervasive that they're harassing someone continually, there has to be accountability," she said.

The prevalence of social media makes the issue more urgent. Brocklebank said children who didn't have an online presence could still be affected because their peers discuss them on Twitter and Facebook and Instagram, and then model their behavior at school based on those discussions.

Brocklebank said her son first began to be bullied in the Xbox gaming community. She first tried talking to the mother of one of the first bullies, then talked to the school, all to no avail.

She urged parents to be more involved in what their children were doing, and to ask questions, even if their children perceived it to be intrusive.

"You have to stay on top of it. You can't trust your kids to understand what their responsibility is … you have to talk to your kids and you have to be involved," she said.

"The overall message, I think, is that it's important for kids to talk about if this is going on at school or online and also if they're feeling depressed, not to feel ashamed and to talk about it to somebody. It's so important."