All it took was one night and one bad decision to destroy what AJ Allmendinger worked 20 years to achieve.

Allmendinger, who earned a coveted ride with Penske Racing this year, tested positive for amphetamine last month during a random drug test at Kentucky Speedway on June 29.

After additional testing, Allmendinger says, the report revealed the substance contained the same chemical compounds as found in the brand-name Adderall.

Allmendinger insists he wasn't "hiding" the facts by not coming forward early in the process. He felt there was nothing he could add until the toxicologists identified the exact substance, the identity of which he believed would help his situation. And until he met with team owner Roger Penske, there was nothing to report on his status, either.

"I'm sure it looked like I was running away," Allmendinger said. "And maybe I could have handled it a little different. But would I still be in the same position? Most likely. Everyone needs to handle things differently. I had to do some soul searching before I came out publicly."

Allmendinger admits he was "scared" to ask his fellow competitors for advice. But he "put his pride aside" on Saturday and called Jeff Gordon. The four-time champion, who has been publicly sympathetic throughout Allmendinger's setback, told the driver to "tell the truth."

So now Allmendinger is talking about what led to his suspension.

"I got to Kentucky early for a few sponsor commitments and went to hang out with a buddy for a couple of days before we got going," Allmendinger said. "We were out early evening. I hadn't been sleeping well -- all season, really with the way things had been going, obviously, the expectations and everything like that. I was really tired, had no energy, nothing. We were out, he had a couple of his friends with him and I was struggling to even stay awake.