Tucson, Arizona (CNN) -- Rep. Gabrielle Giffords joined thousands for a vigil Sunday night in Tucson, Arizona, one of several emotional events over the weekend to mark one year since a shooting rampage left her and 12 others wounded and six people dead.
Soon after the event began, the Arizona Democrat took the stage to lead the crowd in the Pledge of Allegiance. After receiving help from her husband, Mark Kelly, to put her right hand above her heart, Giffords enthusiastically recited the pledge, her voice strong and her demeanor positive, before leaving to applause.
She later reappeared to light a memorial candle, then flashed a wide smile after Dr. Peter Rhees -- a University of Arizona Medical Center doctor who treated her -- said she was loved "nowhere near as much as (in) Tucson" and that the community "was looking forward to having you back" in Washington.
And as the event came to an end, she happily played along with the crowd as it shouted, "Gabby! Gabby!," pumping her hand to the rhythm of the chant.
Kelly himself addressed the audience, highlighting the "strength that ordinary people showed under terrible pressure" in the attack's aftermath.
The retired Navy captain and astronaut also acknowledged that "we all suffered a terrible loss" over those horrific 16 seconds on January 8, 2011, when shots rang out in the parking lot outside a Tucson supermarket.
"Those of us who survived were forever changed by that moment," he said. "For the past year, we've had new realities to live with. ... There are dreams for our family's future that we will just have to let go."
"Even with those painful realities, there is this: The sun still rises over the Rincon Mountains each and every morning," said Kelly, referring to the mountain range around Tucson.
Earlier in the day, the congresswoman's chief of staff, Pia Carusone, admitted that the attack's anniversary has been "difficult emotionally for everybody."
Prosecutors accuse Jared Lee Loughner, 23, of carrying out the attack, which purportedly targeted Giffords during a constituent meet-and-greet event.
On Saturday, Giffords made her first visit back to the parking lot of the supermarket where the mass shooting occurred, Kelly posted on Twitter and Facebook. Carusone said it was Giffords who "wanted to stop by the Safeway."
"It's a very intense feeling to stand in the space where six people lost their lives ... and her life changed," Carusone, who was there with the congresswoman, told CNN on Sunday. "Some memories started to come back."
They also had their "first night out in Tucson" since the shooting and went to personally thank doctors and nurses at the University of Arizona Medical Center on Saturday, Kelly wrote on Facebook.
Giffords then began Sunday by taking a phone call from President Barack Obama to "offer his support."
"The president expressed amazement at the courage and determination Rep. Giffords has shown along her incredible road to recovery, calling her an inspiration to his family and Americans across the country," the White House added in a statement.
Bells rang out around Tucson at 10:11 a.m., the precise moment one year earlier that the shooting occurred, CNN affiliate KMSB reported.
The vigil on the University of Arizona campus capped the emotional day. Emceed by Ron Barber, Giffords' district director who was shot and wounded in last year's incident, the event included tributes to the deceased, a lively musical performance and a request by Tucson Rabbi Stephanie Aaron for everyone to stop and say a prayer every time an emergency response vehicle passes by.
Tucson Mayor Jonathan Rothschild praised how the community has come together since the shooting, helping to "create a more civil ... and a stronger city" that wouldn't be defined by the brazen attack.
"Let us continue to know who we are as a people in Tucson ... united, compassionate, 1 million strong," Rothschild said.
That sentiment was echoed by Ross Zimmerman, whose son Gabe was a staffer for Giffords and among those killed. He told CNN on Sunday that horrible things are a fact of life, adding that what people do going forward in response is what's most important now.
"People can lose their faculties and do terrible things any place in the world," he said. "I would do anything to have Gabe back, but I can't. So what do we do going forward? How do we go forward in ways that help us remember (the victims) and try and do the most positive things we can in response to that?"
Arizona Democratic Party chairman Andrei Cherny released a statement Sunday recalling lessons he said had been learned over "one gut-wrenching, unforgettable year," including that "pure determination combined with love and support can work miracles."
The state's Republican Party issued its own statement, offering its members thoughts and prayers and referring to some post-shooting reactions blaming extreme right-wing thinking and a charged political environment for the attack.
"While our political process was profoundly shaken by this dreadful incident, we have made incredible progress in recovering our hope and faith in (the political) system," the party said.
Sen. Mark Udall, a Colorado Democrat, spoke on his friend Giffords' behalf at a memorial event Sunday. In that speech, he called for more political civility and crossing party lines in Washington and beyond -- a view that Giffords, whom Udall called a "bridge builder," often voiced prior to the shooting.
"The goal isn't bipartisanship, it's results," Udall said. "But bipartisanship is the only way to get results. ... In the end, we're not enemies, we are fellow Americans."
Giffords herself is still recovering from her injuries. Her right side remains weak, and Kelly was at her side Sunday to assist her, as she walked on stage at the memorial event. She has made few public appearances since the incident with some rare exceptions, such as casting a vote raising the federal debt ceiling and an interview with ABC's Diane Sawyer.
She has been undergoing intensive rehabilitation in Houston but has returned to Tucson four times since the shooting, according to her office.
Carusone, the congresswoman's chief of staff, said that Giffords has steadily increased her workload, as her condition has improved.
"As the year wore on, we were able to plug the congresswoman in more," she said. "Now we talk regularly over video chats and telephone. She's gotten more and more involved the better she gets."
Giffords still has not definitively settled on whether she will seek re-election this year, with Carusone predicting that decision will come in the coming months.
"I think, for her, it's a personal decision (and) whether she thinks she can do the job up to the standards she holds for herself," Carusone said.
As to Loughner, he potentially faces the death penalty if convicted on charges of murdering six people -- including the chief federal judge of Arizona, John Roll. He has been diagnosed as schizophrenic and has spent time on suicide watch while in custody and is undergoing treatment in Springfield, Missouri.
A federal appeals court in May cleared the way for him to be forcibly medicated over the objections of Loughner and his attorney.
CNN's Thelma Gutierrez contributed to this report.