Aaron Carter is telling his side of the story after his arrest Saturday for DUI and drug possession in Georgia.

A crying Carter told Entertainment Tonight on Tuesday that prior to the arrest, he had bought a cheap car rather than renting one to get between gigs. But the alignment was off.

"Somebody said I was driving recklessly on the road, that's what the police report said, but the alignment was off on my car, so I went to AutoZone to see if I could do anything about it," an emotional Carter told ET. "A motorcyclist reported that I was swerving all over the road, but the alignment was off a little bit on the new tire."

Carter, 29, says police approached him inside the AutoZone in Georgia and "forcefully" grabbed him out.

"Of course" they knew who he was, said the Sooner or Later singer, who invoked his right to speak to his attorney, but "they disregarded that, they revoked that immediately," he says. "They said, 'Is there anything illegal in the car?"

Carter says he disclosed that there was marijuana in his vehicle. "I kept trying to explain the whole situation, to the officer," he said. "He said, 'You're a professional, right? I'm a professional too, so be quiet.' And then I said, 'OK.'"

The singer was arrested at around 8 p.m. local time in Cornelia, Ga., where he was charged with driving under the influence and possession of less than one ounce of marijuana. Carter's girlfriend, Madison Parker, was arrested for obstruction.

Carter was scheduled to perform Saturday in Kansas City, but had to cancel.

In the interview, Carter came clean about his prescribed drug use, noting that he smokes marijuana for his anxiety, chronic pain and to increase his appetite.

"I do not drink alcohol at all," he said, before clarifying: "I'll occasionally have a sip of a beer or something like that, but I can't even drink IPAs...I don't drink any hard liquor."

Otherwise, he takes "Xanax, Propranolol for high blood pressure medication, and I took oxycodones for my (jaw injury)," he said.

Carter added that the last time he had smoked marijuana was nine hours earlier before the incident with police.

"I do not drink," Carter reiterated. "Hire a polygraph person, a professional. Strap me up."