Sydney Aiello escaped the horrific Valentine’s Day slaughter at Marjory Stoneman Douglas High School with her life.

But just over a year later, she became gunman Nikolas Cruz’s 18th victim.

In a tragic display of the long-lasting effects of gun violence, the 19-year-old committed suicide Sunday and was laid to rest Friday, according to her family.

Aiello died from a gunshot wound to the head, said Heather Galvez of the Broward County Medical Examiner’s Office to NBC News.

The teen’s mom, Cara Aiello, said her daughter was consumed with survivor’s guilt and recently diagnosed with post-traumatic stress disorder from the massacre, according to CBS Miami.

Sydney Aiello couldn’t shake the devastating aftermath of the mass shooting last year, which left three faculty members and 14 students dead, including her longtime friend, Meadow Pollack. She seemed sad in recent days, her mom said, but never asked for help before taking her own life.

Pollack’s father, Andrew Pollack, retweeted someone’s photo of Sydney Aiello and his daughter posing together in fancy gowns with the heartbreaking caption, “A little more than a year after this photo was taken, both are gone.”

Pollack told the Miami Herald that his “heart goes out to [Aiello’s] poor, poor parents.

“It’s terrible what happened. Meadow and Sydney were friends for a long, long time,” he said. “Killing yourself is not the answer.”

The vocal advocate for better school safety added, “If anyone feels like that they have no one that can understand their pain, if there’s any student out there that’s having a hard time, please reach out to me on Twitter. I understand you. You aren’t alone.”

Meadow Pollack’s brother, Hunter, also weighed in on Aiello’s death on Twitter.

“Beautiful Sydney with such a bright future was taken from us way too soon,” he wrote.

Aiello was a senior and on the high-school campus the day of the mass shooting but not in the freshman building where it happened.

After graduating, she enrolled at Florida Atlantic University, according to her Facebook page. But her mother said she struggled to attend class — because she couldn’t bear being back in a classroom.

Before her death, the beautiful teen shared her happier moments on Facebook — amid posts memorializing her slain classmates, including Meadow Pollack, and calling for tighter-gun control laws.

“I’m beyond excited to share that I will be teaching my first yoga class,” she wrote in early September, tagging a yoga studio in Coconut Creek. “This studio is a new beautiful space! Come join me on the mat for a donation only class !!”

But in a seemingly ominous post June 12, she also shared a message about Robin Williams, Kate Spade and Anthony Bourdain — celebrities who each committed suicide by hanging in recent years.

“So, let me say this really loud so the people in the back of the room can hear me…SOMETIMES YOU NEED TO CHECK ON THOSE WHO SEEM THE STRONGEST,” the shared post read.

Aiello’s funeral was held Friday. She was buried at Temple Beth El Memorial Gardens in Davie, Fla., according to an online funeral notice.

She is survived by her parents, Cara and Joseph, and brother Nick.

A GoFundMe page that has been set up to help cover her funeral expenses has soared past $25,000.

“Sydney spent 19 years writing her story as a beloved daughter, sister and friend to many. She lit up every room she entered,” family friends Brett and Blair Israel wrote on the page. “She filled her days cheerleading, doing yoga, and brightening up the days of others. Sydney aspired to work in the medical field helping others in need.”

Ryan Petty, who lost his daughter Alaina in the Parkland shooting, stressed the importance of suicide prevention for Stoneman Douglas students.

“It breaks my heart that we’ve lost yet another student from Stoneman Douglas,” Petty told CBS Miami. “My advice to parents is to ask questions, don’t wait.”

Meanwhile, Cruz appeared in court Friday for a brief pretrial hearing during which his lawyer argued for prosecutors to turn over evidence in the case.

The public defender, Melisa McNeill, accused the Broward County State Attorney’s Office of being slow to produce police officers’ reports and body-camera footage from the day of the shooting.

In a heated exchange with Judge Elizabeth Scherer, McNeill accused the jurist of “putting words in my mouth.”

“You are being disrespectful,” Scherer snapped back.

“Judge, I have to repeat myself so you can understand what I am saying,” McNeill said.

After a brief break, Scherer sided with the defense, telling prosecutors to make sure it has all the evidence it requested.

Cruz, 20, a former Stoneman Douglas student, has pleaded not guilty. His lawyers have said he’ll plead guilty in return for life in prison, but prosecutors are seeking the death penalty.

His trial is tentatively scheduled for next year.

The circumstances leading up to the massacre has been under investigation by Broward County school officials.

On Thursday, teachers learned during a meeting that the school’s principal, Ty Thompson, was also under probe — and has been reassigned, according to the Herald. His day-to-day duties will be handed off to co Principal Teresa Hall, who started at the school a month after the massacre.

Thompson will oversee construction of the new building that will replace the one where the shooting happened.

“Since the tragedy, Thompson has provided stability to the school and community, and has been considered by many to be instrumental in helping with healing and recovery,” said district spokeswoman Kathy Koch.