"Not a day goes by, not even a minute, when I don't think about Jesse and miss him," says Scarlett Lewis of the son she lost in the Newtown massacre

They should be tweens now, discovering algebra, middle school dances and the truth about Santa Claus.

But the 20 first graders of Sandy Hook Elementary School who — along with six of their school’s faculty — were lost in a mass shooting on Dec. 14, 2012, will be forever 6- and 7-year-olds, wiggling their first loose baby tooth and tracing smiley faces on frosty car windows.

“Not a day goes by, not even a minute, when I don’t think about Jesse and miss him,” says Scarlett Lewis of the 6-year-old son she lost that day. “The silence when we came back to the house was deafening and sometimes still is.”

Finding some way to move on is something the victims’ families struggle to do every day since a disturbed gunman’s 10-minute rampage in Newtown, Connecticut, forever changed their lives, their town — and the world.

“It gets harder,” says Hannah D’Avino, whose older sister Rachel, a therapist for children on the autism spectrum, was killed. “You realize what you’ve lost a little more each day.”

For Jenny Hubbard, it’s as if no time at all has passed. “It’s been a blink,” she says.

Marking five years since the massacre, this week’s issue of PEOPLE pays tribute to those who died that day and honors the legacies they left behind.

• Watch the full episode of People Features: Remembering Sandy Hook Elementary — 5 Years Later, streaming now on PeopleTV. Go to People.com/peopletv, or download the app on your favorite streaming device. For more about the Sandy Hook anniversary, subscribe now to PEOPLE or pick up this week’s issue, on newsstands Friday.

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Jesse Lewis
| Credit: courtesy Scarlett Lewis
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From left: Nicole Hockley with son Dylan
| Credit: Courtesy Nicole Hockley Family

For Nicole Hockley, who keeps her 6-year-old son Dylan’s ashes in an urn at her bedside and who co-founded the nonprofit Sandy Hook Promise, working to prevent other school shootings is part of keeping her son’s memory alive.

Hubbard founded an animal sanctuary to memorialize daughter Catherine’s passion for all things furry. It is just one of the many labors of love borne of unimaginable pain.

“The one thing that we are truly fortunate for, and not a day goes by that we don’t acknowledge, is that we’ve been afforded an incredible opportunity in honoring Catherine’s memory and her legacy,” Hubbard says.

“Would I change it for the world?” she continues. “Absolutely. There’s nothing more that I would want then to have Catherine back. But that’s not the reality, and the reality is that she’s gone and I know that I’ll see her again, and in the interim we can do amazing things in her name.”