When a Florida history teacher with stage III colon cancer needed 20 more days off for chemotherapy, he took to Facebook to ask for help and ended up receiving more support than he ever could have expected.

Robert Goodman, 56, who has worked at the Palm Beach Gardens High School for 23 years, posted a photo of himself on July 23 at the hospital and wrote that he already used all of his sick days and had no remaining days.

According to CNN, he decided to take a selfie and post the candid message on Facebook while sitting in a room at the Tomsich Health and Medical Center of Palm Beach County.

“If I can get 20 more sick days from any teacher or district employee volunteers, that would allow me to take more time to recover in battle through chemo for 12 weeks, which should be enough time for me to complete at least the treatment,” he wrote. “So if any of my teacher friends are out there, spread the word for me I would appreciate it. Thank you so much.”

It took just four days for teachers, administrators and lunchroom workers to transfer 75 days to Goodman, who was diagnosed with cancer in April.

“I couldn’t believe it happened so fast,” he told the news outlet.

“Educators all over the country were reaching out to me to donate their sick days, even professors over at Florida Atlantic University,” he added. “I felt guilty because I knew there were people who had it much worse than me.”

At the same time, Goodman wasn’t too shocked that so many people came forward, he tells CNN.

“I wasn’t surprised that teachers were giving. Teachers are always giving all the time,” he said. ” When one of their own needs help they’ll always step up.”

Students too came forward to share “stories of how I’ve positively influenced them was a good reminder of why I chose to teach and why I can’t wait to get back.”

Goodman told The Sun-Sentinel that some people have offered him monetary donations, but he has kindly turned it down.

“It’s not cash in my hand, but it’s paid days of work,” he said of the days that have been donated. “It’s keeping me from going bankrupt.”

While the school year has started, Goodman has begun chemotherapy, which will last until October. He hopes to back at school on January 7, according to the newspaper.

Kathy Burstein, a spokeswoman for the Palm Beach County School District, told the newspaper that teachers receive four sick days at the beginning of the school year. They continue to receive more days until the end of their 10-month contract, she told the newspaper, with a cap at 10 days per school year.

The days, she added, can roll over, and can be cashed out when they retire or can be transferred.

Teacher Dawn McKeich, at the Timber Trace Elementary School in Palm Beach Gardens, donated one of her days to Goodman.

“I wanted to donate because I was really sick three years ago and my fellow teachers stepped up to the plate to help with my classroom and my own children at home. I wanted to pay it forward,” she told The Sun-Sentinel.