DAYTONA BEACH, Fla. — Dale Earnhardt Jr. doesn’t know when he’ll end his winless streak, or how long it will take to turn around his horrendous season.

The only thing NASCAR’s most popular driver — winless in 38 races — is certain of is that he’s not strong enough to withstand another year like this one.

Earnhardt heads into tonight’s race at Daytona International Speedway ranked 19th in the standings and still adjusting to a crew chief change six weeks ago that brought an emotional end to his long working relationship with cousin Tony Eury Jr.

As his struggles snowballed through April and May, it affected everyone in the tight-knit Earnhardt and Eury families.

“I can’t have another year like this. I can’t mentally. I can’t physically. I don’t want to put the people around me through this,” Earnhardt said in a wide-ranging interview with The Associated Press.

“When we were really, really struggling, everybody in the family was upset. Crying and carrying on. All the women were crying, the men we’re cussing. I’m serious. This is our family, Eurys and Earnhardts, racing is our life and it wears on all of them. We can’t put anybody through this (stuff) again. We’ve got to get this right.”

Stoic through the aftermath of his father’s fatal accident in the 2001 Daytona 500, and steady as his popularity pushed him into rock star status, Earnhardt rarely gives a glimpse of any inner turmoil.

So when cracks in his armor began to show in late April, it slowly became clear to team owner Rick Hendrick he’d have to make the split that Earnhardt and Eury were too emotionally invested to recognize how badly it was needed. Hendrick pulled the trigger following a 40th-place finish at Charlotte, replacing Eury with interim crew chief Lance McGrew and assigning additional personnel to Earnhardt’s No. 88 team.

“I feel like we’ve let him down, maybe I’ve let him down, by not pulling the trigger earlier,” Hendrick said. “For maybe his sake and Tony’s sake. Both of those guys are going to be better off.”

That’s been evident for Earnhardt, who admits his confidence was shaken during the rocky first four months of the season.

As Hendrick Motorsports teammates Jimmie Johnson, Jeff Gordon and Mark Martin raced their way into Victory Lane and contention for the Chase for the championship, Earnhardt couldn’t keep pace.

He made rookie-like mistakes, struggled with his cars and led just 84 laps — the bulk coming at Phoenix when Eury used pit strategy to put Earnhardt out front for 63 laps. Through 12 races with Eury, Earnhardt had just three top-10s, and his season-best finish was second at Talladega, where he’s “supposed” to be good.

“I know that I am good enough to drive the car as fast as I need to go. I know how to make the right decisions, I know how to win a race, I know how a championship is won,” he said. “I am not making ignorant mistakes every week to the point where I’m going ‘Wow, what the ... is up with my focus?’ But I did lose a lot of confidence if I would ever get back.

“Not ‘Can I get it done?’ but ‘Am I ever going to run good again, ever? What if this is it?’ And you’re still wondering until you get it turned around.”

So Earnhardt, often criticized for lackadaisical effort, is putting 100 percent into his race team. Those close to him say his commitment has never been greater, and the other three Hendrick drivers have found him to be an engaged, dedicated teammate.

For Hendrick, working with Earnhardt has been far easier than he ever imagined it would be when he signed him to a 5-year deal after Earnhardt had decided to leave his late father’s race team, Dale Earnhardt Inc., at the end of the 2007 season.

“When I first thought about him coming over, a lot of people in this garage said ‘Good luck handling a superstar,’” Hendrick said. “But everything I’ve asked him to do — whether working out, eating better, or showing up at the shop — he’s all over it. He wants to do his part. He’s much easier than I thought he would be.

“I couldn’t ask him to work any harder than he’s working. I don’t care what anybody says. He’s committed. He’s dedicated. And he’s showing up and he’s trying. That’s all I can ask him to do.”

Earnhardt had this current three-race stretch leading into NASCAR’s off weekend circled as his time to click with McGrew and really turn things around. He was an improved 13th last week at New Hampshire, is always a threat to win at Daytona, and a recent tire test at Chicago has him encouraged about next weekend’s race.

And he’s vowed not to let up until he’s back on the right track, racing for wins and his first Sprint Cup title.

“I could work out more than Mark, I could ride a mountain bike farther than Jimmie and I could try to invent a new international language for explaining how a race car drives. There’s all kinds of things I can do differently,” he said. “Making the Chase is going to be (really) hard. I know it. But we’ve still got a shot until they say we don’t. If that doesn’t happen, I need to end this year saying ‘We have repaired it, we have fixed it, this is the direction we’re going and it’s going to be fine.’”