Among those experiencing new hardships is Kristin Jeffcoat, 24, who is raising three children in Camptonville, Calif., a hamlet about 80 miles north of Sacramento. When schools closed last spring, Ms. Jeffcoat, an Instacart shopper, stayed home to watch them. Then her husband got laid off from landscaping work.

The expanded safety net initially caught them: Together, they received more than $1,500 a week in jobless benefits, which exceeded their lost wages. They also received a $3,900 stimulus check, which they used to prepay three months of rent. But since the unemployment bonus ended in July, their cash income has fallen nearly 80 percent.

Now living on $350 a week plus food stamps, Ms. Jeffcoat and her husband have gone without electricity because they cannot afford generator fuel (their house is off the power grid) and have spent weeks without propane for cooking and hot showers. “We stick with cold meals — cereals,” she said.

To feed the children, Ms. Jeffcoat said she sometimes skips meals, especially at the end of the month when the food stamps have run out. Her husband sold his tools to buy diapers, and Ms. Jeffcoat tried to sell her eggs to a fertility clinic, but she did not medically qualify. Worse than the physical hardships is the worry.