On Tuesday, President Joe Biden took new action to combat the surge, pledging to deploy 1,000 military medical professionals to hospitals, open new testing and vaccination sites and distribute 500 million rapid tests to the public for free.

The omicron variant has turned a season of joy into one of weariness and resentment amid a new coronavirus surge.

With days to go before Christmas, Americans are sick and tired of being sick and tired. Of reworking plans to adapt to the latest virus risks. Of searching for at-home tests and not finding them. Of wondering whether, after two years of avoiding COVID-19, or surviving it, or getting vaccinated and maybe even boosted, omicron is the variant they inevitably catch.

A sense of dread about omicron’s rapid spread — the fastest of any variant yet — has swept through the Northeast and Upper Midwest, which were already swamped with delta variant cases and hospitalizations. And unease has burgeoned even in states and territories like Florida, Hawaii and Puerto Rico that had moved past a terrible summer of delta and, until recently, experienced a relative virus lull.

“I’m mad,” said Mabel De Beunza, a publicist in her early 40s who spent 90 minutes at a drive-thru testing line in downtown Miami on Monday after experiencing cold symptoms. No matter what her test result, she has decided against seeing her mother, who is immunocompromised, on Christmas.

“We’ve done so much, and still have this,” said De Beunza, whose family is vaccinated and boosted. “It’s been such a rough year.”

On Tuesday, President Joe Biden took new action to combat the surge, pledging to deploy 1,000 military medical professionals to hospitals, open new testing and vaccination sites and distribute 500 million rapid tests to the public for free.

Some state officials have also imposed new vaccination and mask requirements.

“I know you’re tired,” Biden said from the White House. “I know you’re frustrated.”

He emphasized that the tools available to prevent, diagnose and treat COVID are much more plentiful now than they were in the earliest days of the pandemic.

“We should all be concerned about omicron but not panicked,” he said. “This is not March of 2020.”

Conversations with more than two dozen people across the country revealed that, more than panicked, Americans are simply exhausted by the emotional pandemic roller coaster and confused by mixed messages from experts and leaders about appropriate precautions.

Florida, which long ago did away with almost all virus restrictions, is recording an average of 7,068 daily coronavirus cases, a 294% increase over the past two weeks, according to data compiled by The New York Times.

The rise was sudden and jarring after a couple of months of relative virus quiet that followed a delta surge that killed more than 22,000 Floridians, more than any previous virus wave, according to Jason L. Salemi, an epidemiologist at the University of South Florida.

But winter is Florida’s high season, drawing part-time residents and throngs of visitors. Some attendees reported testing positive for COVID this month after going to events related to the Art Basel Miami Beach fair.

On Tuesday, the office of Mayor Daniella Levine Cava of Miami-Dade County said a state-run clinic had run out of monoclonal antibody treatments. The Florida Department of Health said sites in several counties closed for training Tuesday but acknowledged that some appointments had to be rescheduled and that the state was trying to secure a resupply.

“All my friends in Miami have COVID right now,” Fabiana Vegas, 21, said Tuesday as she waited in line to get tested in Orlando. “I wanted to go to Miami this Christmas, and I can’t.”

Cases have also skyrocketed in Hawaii, with the state reporting a daily average that is 468% higher than it was two weeks ago, according to data from The Times.

Nowhere has there been a larger explosion of cases than in Puerto Rico, which has recorded a daily average of 1,098 — a 762% increase from two weeks ago, according to data from The Times. The sharp rise prompted Gov. Pedro R. Pierluisi to authorize new restrictions, including requiring vaccinations and negative tests for large events.

Marisa Gómez Cuevas, 34, tested positive after going out to a bar in Old San Juan to meet friends that she had not seen in months. A few days later, she started getting calls from some of those friends, saying they felt sick. One ended up in a hospital.

She lost a gig she had with a theater production last week, and is scared to return to her waitressing job.

“I worry there will be another outbreak, and it will have to close again,” she said of the small family-owned restaurant where she works.

In other parts of the country that have been suffering from high caseloads for longer, restrictions have offered residents some peace of mind. Boston mandated proof of vaccines in restaurants and other indoor spaces Monday, giving some relief to Christopher Glionna, the managing partner at the Aquitaine Group, which owns several eateries in the city’s South End.

“It is good for business,” he said. “People want to get together.”

Still, in states that have not yet experienced the latest virus surge, some people are already on edge.

In Berkeley, California, Brian Edwards-Tiekert, 43, a public radio host, and his wife changed their COVID protocols this week after realizing how fast omicron was spreading.

“We’re not going to see anyone without testing,” he said. “And we’re upgrading from cloth masks to N95s or the equivalent.”

His wife ran out to pharmacies in search of at-home rapid tests and found only three — enough to use before a dinner Wednesday, but not to prepare for another social engagement Thursday.

The emotional whiplash inherent in all the worry and planning is draining, Edwards-Tiekert said, describing two tabs permanently open on his web browser: the California rain forecast and a COVID tracking dashboard.

“I guess I’m a little bit numbed at this point,” he said.