Melissa Zeidan was running errands in her San Francisco neighborhood on Tuesday - filling her car's gas tank, returning some clothes - while two of her young children were at school. When she learned the news of the shootings in Uvalde, Texas, she immediately started sobbing.

"When it's an elementary school, it hits in a different way," said Zeidan, 42, who is parent to a first-grader, a pre-schooler and a toddler.

By Wednesday, her grief and fear morphed into anger and action. She said her friends, other parents, felt the same way. A self-described political neophyte, Zeidan joined Moms Demand Action, which advocates for stricter gun laws.

"I'm so enraged," Zeidan said. "We can't just let this pass this by and not do something to try and make a difference."

In the hours after a teenage gunman killed 19 children and two teachers at Robb Elementary School, mothers and fathers across the United States turned to social media to vent, plead and pray.

Some urged their friends to contact elected officials and push them to pass gun law reforms. Others mourned for the Texas parents who didn't get to tuck their children into bed Tuesday night, and shared how scary it felt to send their own little ones back to school on Wednesday morning.

Many grappled with how to talk to their kids about yet another shooting, this one coming so quickly after a gunman killed 10 shoppers at a Buffalo, New York supermarket on May 14. The Uvalde massacre also stirred memories of the students senselessly killed in mass shootings in Newtown, Connecticut in 2012 and Parkland, Florida in 2018.

Mary Kate Roach, 41, lived near Newtown with her 1-year-old son when the killings at Sandy Hook Elementary occurred. The unfolding tragedy in Uvalde brought it all rushing back.

"When I heard about what happened, I had that same visceral reaction as I did nine years ago," she said. "I thought I was going to vomit. I sobbed for the rest for the day."

Her son is now 9 and in third grade, close in age to the Texas victims.

"At some point I will have to talk to Johnny about it, explain what happened and answer his questions," Roach said. "I will also have to reassure him that he is safe at school. I will be lying of course because there is no way for me to tell him that with complete certainty or confidence."

PARENTING PERILS

It has been tough to be a parent of late. The COVID-19 pandemic kept kids out of school for months on end, stalled their learning and triggered job losses.

More recently, parents have struggled with higher prices for staples such as food and gasoline while a shortage of baby formula has made it harder for some to feed their infants.

"The anxiety is unrelenting," said Rebecca Falzano, 40, a writer in Falmouth, Maine and mother of two.

For some veterans of the gun-control movement, Uvalde brought a sense of deep resignation over the lack of action by federal lawmakers since the Sandy Hook shootings.

"Nothing has changed," said Kim Parker Russell, 53, a mother of two in Brooklyn who was spurred by Sandy Hook to become an activist with Moms Demand Action.

"For the first time ever, I am at a complete loss," Russell said. "Sending people to the polls isn't enough. We fucking did that. Biden, a Democratic Congress. We did our job, and we're still not able to get this done."

A school district in New Salem, New York, just 25 miles from Newtown, told parents on Wednesday that it was increasing police patrols because of the similarities between the Uvalde and Newtown shootings. Another district in Houston, Texas tried to reassure parents that there were currently "no active threats."

"I will hold my children a little tighter when I see them as I'm sure many of you will as well," said Houston independent school district superintendent Millard House. "Let us hold the families of those who have lost loved ones just as tightly in our thoughts."

Kristen Schnaekel, 51, an early childhood teacher and mother of three in Centreville, Maryland, recalled how after Sandy Hook, she had to prep her 5-year-old students for active-shooter drills while trying to keep tears from streaming down her cheeks.

"I thought surely something was going to change, she said. "I've been in a pretty bad mood all day."