Wednesday was one of the deadliest days in American history, topping D-Day, 9/11

TOPSHOT - Medical personnel move a deceased patient to a refrigerated truck serving as make shift morgues at Brooklyn Hospital Center on April 09, 2020 in New York City. - America's coronavirus epicenter of New York recorded a new single-day high of

Just when the U.S. appears on the verge of rolling out a COVID-19 vaccine, the numbers have become gloomier than ever: Over 3,000 American deaths in a single day, more than on D-Day or 9/11. One million new cases in the span of five days. More than 106,000 people in the hospital.

The crisis across the country is pushing medical centers to the breaking point and leaving staff members and public health officials burned out and plagued by tears and nightmares.

All told, the crisis has left more than 290,000 people dead in the U.S, with more than 15 million confirmed infections.

The U.S. recorded 3,124 deaths Wednesday, the highest one-day total yet, according to Johns Hopkins University. Up until last week, the peak was 2,603 deaths on April 15, when New York City was the epicenter of the nation’s outbreak.

Get your top stories delivered daily! Sign up for FOX 11’s Fast 5 newsletter. And, get breaking news alerts in the FOX 11 News app. Download for iOS or Android.

Wednesday’s toll eclipsed American deaths on the opening day of the Normandy invasion during World War II: 2,500, out of some 4,400 allied deaths. And it topped the toll on Sept. 11, 2001, as well: 2,977.

New cases per day are running at all-time highs of over 209,000, by Johns Hopkins’ count. And the number of people in the hospital with COVID-19 is setting records nearly every day.

A U.S. government advisory panel convened on Thursday to decide whether to endorse mass use of Pfizer’s COVID-19 vaccine to help conquer the outbreak that has killed close to 300,000 Americans. The meeting of outside advisers to the Food and Drug Administration was the next-to-last hurdle before the expected start of the biggest vaccination campaign in U.S. history.

Depending on how fast the FDA signs off on the panel’s recommendation, shots could begin within days.

RELATED: Stay up to date on all coronavirus-related information

In St. Louis, respiratory therapist Joe Kowalczyk said he has seen entire floors of his hospital fill up with COVID-19 patients, some of them two to a room. He said the supply of ventilators is dwindling, and the inventory is so thin that colleagues on one shift had to ventilate one patient by using a BiPAP machine, similar to the devices used to treat sleep apnea.

When he goes home to sleep during the day at the end of his grueling overnight shifts, he sometimes has nightmares.

“I would be sleeping and I would be working in a unit and things would go completely wrong and I would shock myself awake. They would be very visceral and very vivid,” he said. “It would just really spook me.”

In South Dakota, Dr. Clay Smith has treated hundreds of COVID-19 patients while working at Monument Health Spearfish Hospital and at Sheridan Memorial Hospital in neighboring Wyoming.

He said patients are becoming stranded in the emergency room for hours while they await beds on the main floor or transfers to larger hospitals. And those transfers are becoming more challenging, with some patients sent as far away as Denver, 400 miles from the two hospitals.

“That is a huge burden for families and EMS systems as well when you take an ambulance and send it 400 miles one way, that ambulance is out of the community for essentially a whole day,” he said.

Smith added that some patients have gone from thinking “I thought this was a hoax” to “Wow, this is real and I feel terrible.” But he has also seen people with COVID-19 who “continue to be disbelievers. It is hard to see that.”

“At the end of the day the virus doesn’t care whether you believe in it or not,” he said.

In New Orleans, city Health Director Dr. Jennifer Avegno described a recent visit to a hospital where she watched doctors, nurses, respiratory therapists and others risk exposure to the disease in a long, futile attempt to save a dying COVID-19 patient. Some broke down in tears afterward, she said.

“These are seasoned emergency and critical care personnel,” she said. “We do not cry very often — and especially not a number of us all at once.”

She cited “the sheer exhaustion of giving their all for similar patients over and over and over again for the past nine months, coupled with the knowledge that much of this could be prevented with really simple measures.”

In Virginia, Gov. Ralph Northam, a doctor by training, announced a midnight curfew and expanded mask rules to require the wearing of face coverings outdoors, not just inside.

In New York City, which was ravaged by the virus in the spring, one doctor sounded a note of relative optimism, saying that at least physicians are more capable of managing the virus now.

“Early in the spring we did not know enough,” said Dr. Jolion McGreevy, who directs Mount Sinai Hospital’s emergency department. “We really are operating from a place of knowledge, now — which is a big leap from where we were in the spring.”

The grim figures from Wednesday led the usually stoic health director of the nation’s most populated county to become emotional. Barbara Ferrer described “a devastating increase in deaths” in Los Angeles County, with the total hitting 8,075 on Wednesday.

“Over 8,000 people who were beloved members of their families are not coming back,” Ferrer said, fighting back tears.

Ellen DeGeneres, meanwhile, became one of the latest celebrities to be infected with the virus, though she said she is “feeling fine right now.” Production on her talk show was put on hold until January, and reruns will air in the meantime.