By Christina Maxouris, CNN

(CNN) -- Brittany Smart has spent months tending to the Covid-19 patients who poured into Texas hospitals as the virus raged across the state -- and the country.

It has been devastating, the ICU nurse told CNN's Chris Cuomo Tuesday night, speaking right after the end of another shift.

Health care workers had begun to see a light at the end of the tunnel, she said, amid ongoing vaccinations and after several weeks of declining Covid-19 cases. But that was "shut down" when Texas Gov. Greg Abbott announced he was lifting the statewide mask mandate and capacity limits on businesses, Smart added.

"We're all pretty exhausted and I'm scared of what this is going to look like," she said.

Smart said she doesn't think now is a safe time to take away the mask mandate and called the governor's move "nerve-wracking."

Covid-19 trends across the US may have been encouraging for a while, but Centers for Disease Control and Prevention Director Dr. Rochelle Walensky warned earlier this week that recent steep declines in cases now seem to be "leveling off at still very high numbers."

The US has averaged more than 65,000 new Covid-19 cases daily for the past week, according to Johns Hopkins University data. More than 46,300 people remain hospitalized with the virus nationwide, according to the COVID Tracking Project.

Texas announced more than 6,600 new Covid-19 cases Tuesday and more than 270 newly reported Covid-19 deaths, according to state data.

More than 5,600 Covid-19 patients remain in the state's hospitals, the data shows.

"It's not like the Covid patients are gone," Smart said. "It's not like they're not dying. It's just that we no longer need a refrigerated truck outside, is the deal."

"We don't have people in the hallways anymore, stretchers," she said. "So, breathing is a little bit easier but... it's not better."

And experts have warned the country could see another surge in just a matter of weeks, fueled by highly contagious variants already circulating in the US. That's why, they've cautioned, it's critical not to let up on safety measures just yet.

"My biggest fear is that we're going to lose more people," Smart said.