A New York doctor who’s been treating coronavirus patients says she’s still reeling days after getting a devastating letter: Her green card application was denied.

“I’m putting my life on the line every day to do this, and it’s just blowing my mind right now that they are not appreciating it or they don’t see the value in what I’m offering to do,” Dr. Julia Iafrate told CNN’s Chris Cuomo on Tuesday. “I’m honestly beside myself. It’s like a slap in the face.”

Iafrate is an assistant professor at Columbia University Medical Center who specializes in sports medicine. But she says she wanted to volunteer to work on the front lines as coronavirus cases spiked in her city.

“Because I’m a doctor,” Iafrate said, “because that’s what I do, because I know that I can help.”

Iafrate, who immigrated to the United States from Canada, says she’s lived in the US for 13 years, completing a residency program at the Mayo Clinic and a sports medicine fellowship at the University of Iowa. For almost three years, she’s been working at the Columbia University Medical Center. And she’s been a team physician for the USA Ski Team and Columbia University Athletics, according to a profile on the medical center’s website.

Several days ago, Iafrate says she heard from US Citizenship and Immigration Services that her green card application had been denied.

“I was blindsided. I was flabbergasted, and so was my immigration lawyer and so was my chair of my department and everyone else involved in this case,” she said. “They ask you to be an expert in your field … and I am. I’ve proven that time and time again. And I was just blown away that at this time, of all times, they don’t think it’s necessary to have someone like me here.”

Asked about Iafrate, US Citizenship and Immigration Services said in a statement that it doesn’t comment on decisions related to individual cases.

“USCIS evaluates each petition, application and request on a case-by-case basis to determine if they meet all standards required under applicable laws, regulations, and policies. Agency adjudicators may request further evidence and issue subsequent denials when the petitioner provides insufficient evidence to establish eligibility based on the preponderance of the evidence standard,” the agency said. “It is incumbent upon the applicant — not the government — to show that the prospective beneficiary meets the requirements for eligibility under the law.”

The Trump administration has tightened immigration restrictions in recent weeks as part of the government’s response to the coronavirus pandemic and warned that more restrictions could be coming as officials work to protect American jobs. Immigrant rights advocates argue that immigrants are on the front lines fighting the pandemic, and that their work is a necessary part of the country’s economy.

Iafrate says she’s appealing the government’s decision in her case.

She told Cuomo she feels helpless for the first time in her life.

“It’s heartwrenching. … I don’t know what to do. I don’t know what I could have done better,” she says. “I don’t know what I could have done any differently.”