CHICAGO (CBS) — A 10-year-old boy was grieving Monday night, after his mother was gunned down doing something as simple as driving by in her car.

As CBS 2’s Eric Cox reported, 46-year-old Shaunte Stewart was headed home after celebrating her own birthday early Sunday morning when she was shot and killed in the Washington Park neighborhood.

Stewart’s son, Shamar, is wise beyond his years. Talking about it was hard for him, but he shared his feelings about the morning he lost his mom.

“I can’t stop thinking of my mom,” Shamar said.

Thoughts swirled inside Shamar’s head. The 10-year-old sat beside his grandfather as he spoke with Cox.

He talked about Saturday, when his mother went out to celebrate her birthday.

“My mom left out at around 10 o’clock,” Shamar said.

She left at 10 p.m. and called her son around 1 a.m.

Little did Shamar know it would be the last time he’d ever hear her voice.

“The last thing that she ever said to me was, ‘You want me to come home?’ And I said no, because I was having a good time watching TV,” Shamar said. “I didn’t know nothing was going to happen.”

Stewart hopped in the car and started heading home shortly after 4:15 a.m. Sunday. She was traveling south in the 5100 block of South Prairie Avenue when someone fired shots from the sidewalk.

“Well it just was shocking – a big shock to me,” said Gene Barnes, Ms. Stewart’s father. “You never know what’s going to happen. You never know what to expect.”

Barnes never expected his daughter would be hit in the arm and neck with bullets while celebrating her own birthday.

Her car continued moving, taking out a fence before striking a pole on the next block. She was taken to the University of Chicago Medical Center, where she was pronounced dead.

Shamar said his grandfather told him the tragic news. The moment, of course, is etched in his mind.

“It hurts,” Shamar said, “It hurts to find out that one of the people that’s most important to you has passed away.”

Police said Ms. Stewart was not the intended target.

A man was riding in her passenger seat. Detectives could not say if the shots fired were meant for him.

Sitting on a front porch as the cicadas sang around them, Cox asked Shamar how he was feeling a couple of days after he lost his mom.

“It feels like this is a dream,” Shamar said. “I wish this was a dream.”

Stewart was a U.S. postal worker. She is the second postal worker who has been shot and killed while behind the wheel in Chicago this year.

Her union expressed sorrow over the weekend. Her son, meanwhile, is staying as strong as ever as the family deals with such an untimely death.