"I started crying," the professional ballroom dancer, 32, tells PEOPLE. "I hadn't even taken a step yet. Just to stand tall was extremely emotional."
In this week's PEOPLE cover story, featuring candid interviews and an exclusive photo portfolio taken on May 30 at Spaulding Rehabilitation Hospital in Charlestown, Mass., Haslet and 10 other survivors – including nine amputees – reveal how they've been coping since the April 15 blasts that claimed three lives and left as many as 264 people injured.
The lives of the 16 people who lost limbs that day were forever changed.
Now, even basic tasks like going to the bathroom and taking a shower in the morning "take double the time," admits Haslet.
But by leaning on each other, they're helping each other heal both physically and emotionally.
Among the most grievously hurt were Marc Fucarile, 34, of Stoneham, Mass., and Roseann Sdoia, 45, of Boston, who are featured in the issue and exclusive PEOPLE videos.
Stranded when the last available ambulances raced past them, the pair were thrown in the back of a police van to be rushed to the hospital.
As the vehicle hurtled through the streets of Boston, Fucarile, whose right leg was blown off, drifted in and out of consciousness. "I thought I was going to die," says the father of a son, Gavin, 5.
But with soothing words, Sdoia, who also lost a leg, kept him awake and pushed him to fight for life.
Now Fucarile and his fiancé Jennifer Regan, 30, are looking forward to planning their wedding again.
"I definitely want to be able to dance," says Fucarile.
For more of these survivors' inspiring stories, pick up the latest issue of PEOPLE, on newsstands Friday