TULSA, Oklahoma - Nearly 51 years since the assassination of John F. Kennedy, the special agent who was in the motorcade with the president is still haunted.

It's a day that has stayed with Clint Hill for decades as he suffered from post-traumatic stress disorder, something he's now helping other service members deal with.

Thursday, he was honored in Tulsa.

November 22, 1963 is still difficult for Hill to talk about; he's been dealing with pain ever since, but now he's helping other service members deal with similar issues.

More than 50 years later, Hill still gets emotional when recalling what Jacqueline Kennedy said to him moments after John F. Kennedy was shot.

"Oh Jack. Oh Jack, what have they done? I have his brains in my hand. I love you, Jack. That's all she said," Hill recalled.

Hill is the special agent in the iconic video, jumping into the president's limousine to shield him.

"I saw the president. He grabbed at his throat, he moved to his left. It was very unusual activity. I knew something had happened. Something was wrong," Hill said.

He remembers every detail of that day.

"I could see that his eyes were fixed, there was a hole in his skull. I could see that a great portion of his brain was missing, and I assumed immediately that it had been a fatal shot and that he was dead. That will always be in my mind," he said.

Hill said he buried his feelings from that day, and the days to follow, for years. He said he still carries some guilt.

"We failed,” Hill said. “We had a responsibility to keep the president from being assassinated and we were not able to do that and it just started to really eat at me."

For decades, he crawled in a bottle.

"I was really drinking myself to death and I just lived on cigarettes and tobacco, or cigarettes and alcohol," he said.

It took the trust of journalist Lisa McCubbin in 2009, and her interest in writing a book about Hill, to pull him out of his pain.

"He always walked with his head down. He was always looking down," McCubbin said.

Hill and best-selling author have co-authored two books together, Mrs. Kennedy and Me and Five Days In November. They are working on another book that will chronicle Hill's service during several presidencies, from 1958-1975.

Hill said writing the books has changed his life.

"My ability to get that information out and release it, it was like a weight had been lifted off my shoulders," he said.

Hill suffers from post-traumatic stress disorder, a disorder that's only now being talked about among service members.

He's in Tulsa this weekend because of a cottage at Skiatook Lake which now bears his name.

11/20/2014 Related Story: Crews Making Progress On Remodeled Skiatook Overlook

A non-profit called Partners for Heroes intends it to be a place where people with PTSD can begin to heal; a process that Hill is still moving through more than 50 years later.

"Talking about it and writing the book about it has really been beneficial to me," he said.

Hill said he wanted people to know that Jackie Kennedy was not just a Barbie doll. He said she was down to earth, laid back, intelligent and fun-loving.