As the 20-year mark since the Sept. 11 attacks approaches, two Connecticut health care professionals are sharing their experiences working in New York hospitals on that fateful day.

"There are certain things that bring you back, you know, the September sky in New York brings me to that day every time I look up and there's not a cloud in the sky," says Dr. Frank Illuzzi, Hartford HealthCare's medical director for specialty services.

Illuzzi was the chief resident at Long Island Jewish Medical Center in Queens 20 years ago when terrorists flew two planes into the World Trade Center.

"We didn't even send an alert out and I had 100 doctors and nurses show up immediately, just instinctively saying, 'How can we help?'" Illuzzi recalls.

MORE: COMPLETE COVERAGE: 9/11 - 20 Years Later

Illuzzi says the hospital immediately enacted its disaster plan, preparing for an onslaught of patients, an estimated 500 to 1,000. But he says only a dozen or two came -- the number of survivors was far fewer than first thought.

"It was really deflating. It was an awful, awful, sinking feeling. I mean, anybody who went through it. That day just kept getting worse and worse and worse and worse, the whole day," Illuzzi says.

Hartford HealthCare's president and CEO Jeff Flaks also witnessed it first-hand.

Jeff Flaks worked at St. Vincent's Hospital in lower Manhattan, less than 2 miles from the World Trade Center.

"We were actually in our boardroom having a meeting and we heard a loud noise," Flaks recalls. "At the hospital campus, they immediately closed down Seventh Avenue. All of our doctors and nurses sprang into action and really created hundreds of beds on Seventh Avenue between 11th and 12th Street."

Flaks says the initial rush brought more than 300 patients who were physically hurt, but also emotionally traumatized. He also remembers the faces of so many family members learning their loved ones hadn't made it to the hospital.

"It was devastating, just devastating. Certainly, something I will never forget," Flaks says.

Twenty years later, it's still hard.

Illuzzi says every anniversary reopens old wounds, but he's found a personal remedy.

"I try to, you know, dwell on all the good things that people did that day to help each other and that's how I try and get through this day," he says.