"I just couldn't breathe. It was like I had ran a 3- or 4-mile run, you know how you feel when you get like that? And all I did is work out," Chapman, who traveled to the hospital without an ambulance, said. "So there's something haywire or it's psychologically. I don't know, you know? I guess things happen like that."
"I don't do drugs and really didn't do drugs like they do today. We didn't have that back in the '60s, right? Or '70s," he continued. "A lot of psychological things go through your mind when this happens, you know? So something's gotta break."
While Chapman, who's still undergoing tests to determine the cause of the scare, said that "it feels much better now," he reiterated the severe grief he's continuing to suffer.
"I'm going through some psychological things right now too, so that doesn't help," Chapman said. "I think, basically, I had a broken heart. And of course, it's going to heal."
A source close to Chapman confirmed his weekend hospitalization to ET earlier this week, while a rep for the TV personality said, "I can confirm Dog is under doctor's care and is resting comfortably. Thank you for all of your well wishes -- keep 'em coming."
On Tuesday, a rep for Chapman told ET that he was doing well after being discharged.
"Dog is back at home and resting comfortably," the statement read in part. "He is overwhelmed by the support of fans and friends from around the world, and is deeply touched by the outpouring of prayers, love and encouragement."
A source familiar with the situation also told ET that Chapman checked out of a Colorado hospital late on Monday night, after doctors determined that the pain he had experienced was caused by high blood pressure and stress. The source added that after going to hospital, Chapman underwent an angiogram, which came back clear, and that he would not require any surgery.
Back in July, Chapman told ET about the impact his wife's death had on his health, which included him losing 17 pounds.
"I can't eat. Two bites, I'm full," he said at the time. "I got to force feed myself like I force fed her."
Watch the video below for more on Chapman.