(CNN)When the bell rings at Casa Grande Union High School, more than seventy sophomores pile into Stacy Brady's biology class.
The rural school district outside Phoenix can't find enough certified teachers, especially for math and science, so 13 classes are doubled up, with several holding more than 70 students. Some of those classes get a teaching assistant, but others rely on a single teacher.
"It's been very chaotic," Brady said. "I wish I could clone myself because I can't get to every kid who needs help."
Situated between Phoenix and Tucson, Casa Grande has struggled to find teachers for years, hiring roughly 30 from the Philippines each year to fill the gap. But that alarming trend is hitting a more dire point. Jennifer Kortsen, a district spokesperson, says, in her 29 years here, she's never seen a shortage like this.
"I've never had a school year start where we've had so many vacancies, and it's really sad," Kortsen said. "We have it posted, we've gone to job fairs, and there's simply no teachers out there to be had right now."
After two years of weathering pandemic health concerns, learning loss, and tense public scrutiny, teacher burnout is surging nationwide.
Jennifer Zanardi just quit her high school teaching job in Palm Beach, Florida, to become a corporate recruiter. She says the relatively low salary was a big factor, but the political pressure and the state's so-called "Don't Say Gay" bill were the tipping points. She found herself working more hours and walking on eggshells.
"The public was actually saying that teachers were trying to indoctrinate students," Zanardi said. "It affected my mental health and my stress in a huge way."
Enrollment in teacher preparation programs is also plummeting, down 33% between 2010 and 2020 -- a trend that has only intensified during the pandemic, according to the American Association of Colleges for Teacher Education.
Schools are competing for a shrinking pool of teachers, and wealthier suburban districts are winning out over those with fewer resources, especially rural schools and those that support more low-income families and students of color.
"(Teachers) are not going to the schools that are the most disadvantaged," said Chad Aldeman, policy director of the Economics Lab at Georgetown University. "The same schools that were struggling in 2019 are struggling even worse in 2022."
In Prince George's County, Maryland, where there's a high concentration of poverty, at least 8 percent of the public school district's teacher slots are vacant, more than twice as many as last year, according to the teachers union.
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Dr. Donna Christy, the president of the Prince George's County Educators Association, is seeing a scramble to fill the gap.
"It definitely feels like there's been an exodus," Christy said. "They're leaving the profession, but they are leaving for other districts as well. Where there's higher pay, where there are better working conditions, where they feel more supported, or they've heard there's more support."
Geva Hickman-Johnson, a high school English teacher in Prince George's County, just found out she'll need to prep lessons for the new substitutes in her department. She also expects her class sizes to grow.
"It means that my students may not be getting the best teacher this year," Hickman-Johnson said. "I may not be able to be at my best because I'm being pulled in so many different directions that I'm not going to really be able to focus on the students that I'm standing in front of every day. It's hard."
On top of learning loss during the pandemic, many teachers across the country have also noticed worsening student behavior. At a time when many students need more attention, Christy fears they'll receive less.
"They were falling through the cracks before," she said. "It's going to be like opening the floodgates. It's going to be really hard to keep up with our struggling students."
Like many districts, Prince George's County Public Schools are now scrambling to fill those empty classrooms, shifting staff around, increasing pay for subs, and combining classes when necessary.
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States are getting creative to fill vacancies, though some of the plans are controversial. In Florida, Gov. Ron DeSantis is asking veterans with no teaching degree to lead classrooms.
"It was a slap in the face," Jennifer Zanardi said. "Like what you do doesn't matter, your education doesn't matter, anybody can do what you do. And that's simply not true. We're professionals."
Casa Grande Elementary School District is one of many that have moved to a 4-day week to retain staff -- a strategy it says helped them keep several teachers.
The high school district is looking to hire more teachers from overseas. In some classrooms, paraeducators without expertise on the topic are teaching lessons prepared by certified teachers, like Stacy Brady.
"I think of myself," Brady said. "I struggled with math. And if I was sitting in that classroom, I needed help, I had questions, I needed somebody to break it down a different way, and there was nobody who has the content knowledge to do that, I (would) shut down. And I'm thinking many of our students might be shutting down as well."
Brady expects to lead classes with 70-plus students most, if not all year. She fears the teacher shortage in Casa Grande is only going to get worse.
"My biggest fear, I think, is that some kid is getting hurt in some way, emotionally or physically," she said. "And I'm not able to see it, because there are so many students in the room."