A young mother was driving her sons to a sledding excursion in Grand Rapids, Mich., when her car stalled along U.S. 131, her family says.

Valery Arreola, 21, was eight months pregnant. Her two sons, 3 and 5, were with Arreola in the car at 1:30 p.m. on Jan. 7 when she pulled to the shoulder, her family told WOOD-TV.

“She calls my dad and says, ‘Hey, my car just stopped. What do I do?’ ” Nohemi Arreola, her sister, told WOOD-TV. “And he said, ‘Don’t worry, we’re on our way, we’ll come and get you.’”

But the next thing her father heard over the phone was a loud crash, the sister told the TV station. Then there was silence.

A pickup had just hit Arreola’s 1999 Nissan Altima from behind, Fox 17 reports.

Minutes after the pickup struck her vehicle, Arreola could be heard begging for help as Martin Junglas, another driver, approached the wreck, he told Fox 17. Junglas watched as firefighters used the Jaws of Life to cut open the vehicle, he said.

“Her only concern was for her children,” Junglas told Fox 17. “She didn’t care about her injuries or her pain. She just wanted to make sure her children were all right.”

Arreola and the 3-year-old son were taken to the hospital in critical condition, WOOD-TV reports.

Doctors were unable to save Arreola and her unborn child, but they are treating the 3-year-old for internal bleeding and fractures to his skull, legs and shoulder blade, the family wrote on a GoFundMe page raising money for the funeral arrangements.

Arreola’s 5-year-old son was remarkably unharmed, the family said.

“He made it out with just two scratches on his face, thank God,” Nohemi Arreola, the sister, told WOOD-TV. “His guardian angel was really watching him.”

The driver of the Ford F-150 pickup that hit Arreola’s vehicle from behind was taken to the hospital as well, the Detroit Free Press reports, and he was treated and released.

The Michigan State Patrol said that neither speed nor alcohol are believed to be factors in the incident, but an investigation is ongoing.

“[S]he knew as she passed away that her children were safe,” Junglas, the man from the accident scene, told Fox 17. “I had told her that as I left the vehicle that her children were safe and would be okay."

As of Jan. 9, the family had raised more than $11,000 toward their $25,000 goal on GoFundMe.

“Hug your loved ones and never take them for granted,” the family wrote on the fundraising page.