One Thursday you’re waking up in Reno, Nev., thinking you soon will head to the park for another minor league game, wondering what may be for breakfast at the team hotel.

By the next Thursday — May 2 — you’re in the thick of a trying major league season, trying to figure things out, trying to make sure that one mistake doesn’t lead to another and then another one after that. That’s the difference a week can make in the major leagues. Carter Kieboom is learning fast.

“I’m not going to sugarcoat anything,” Kieboom said at his locker late Wednesday night, toward the back of the Washington Nationals’ clubhouse, an oval-shaped-room that was quiet and emptying after a sixth loss in seven games. “Yeah, I should definitely be doing better.”

It has been seven days since the Nationals’ top prospect was recalled from the Class AAA Fresno Grizzlies to provide a shot of energy for a struggling team. The 21-year-old has been that in short bursts. He hit a game-tying home run against the San Diego Padres in his debut April 26. He hit a game-tying solo homer two days later. He is playing in place of injured shortstop Trea Turner, who could miss another month with a broken right index finger, and Washington was ready for Kieboom’s upside to clash with any growing pains.

But Kieboom’s struggles have overshadowed his promise, albeit in just a six-game sample size. He struck out twice against the Cardinals on Wednesday and has done so nine times in 22 at-bats. He also made a costly eighth-inning error that helped St. Louis stretch its lead to four runs. His defense, the reason General Manager Mike Rizzo did not immediately promote him when Turner got hurt April 2, remains a work in progress.

Kieboom didn’t shy away from any of that Wednesday, in the minutes after the worst game of his young career, in another spot he had never been in, surrounded by reporters. He only promised to come back the next day and try again.

“He’s just young. You’re a young 21-year-old kid playing in the major leagues,” Nationals Manager Dave Martinez said after Wednesday’s defeat. “Sometimes you come up here and the game speeds up on you a little bit. We just have to get him to slow down, relax and play the game the way he’s always been playing his whole life.”

That is how Kieboom got here. That’s how he hit .379 with a .506 on-base percentage in 18 games for Fresno this season. That’s how this gets fixed.

Yet since April 25, since he woke up to a bunch of missed calls, since Fresno Manager Randy Knorr told him the news and he didn’t know what to say, everything has moved at a nonstop pace. He flew to Washington with a suitcase packed for just a few days. He bought new dress clothes once he landed, and he needed contact solution, and by 3 p.m. April 26, he was sitting in a crowded news conference room and talking about this dream. Then, hours later, he hit that homer for his first big league hit. Then, an inning after that, he struck out in the bottom of the ninth with the bases loaded for the final out. Then his phone flooded with more tweets and texts than he could answer across the next three days.

Then, for the first time, he went to sleep as a major league baseball player. Then, overnight, his life changed.

“It’s like nothing I had ever experienced,” Kieboom said Sunday of those first 24 hours. “It was just one thing after the next. Whirlwind is the perfect word.”

By Saturday morning, Kieboom couldn’t go anywhere around the ballpark without being recognized. He rode a scooter through the Navy Yard, and fans shouted “Good game!” along the sidewalks. He stood by Philz Coffee, scrolling through those unread messages, and a woman poked her head out of the door to say, “Hey Carter, you were awesome last night.” This is how you picture it, succeeding in a packed stadium, swatting one over the fence, springing out of the dugout for a curtain call because the crowd won’t stop cheering. Everyone knows you after that. And it’s for the right reasons.

But there is always another side to it. The mistakes are magnified at this level, and Kieboom felt that Wednesday. In the first inning, with the Nationals already trailing, he waited on a groundball and let a runner shift his path to it. Martinez wanted him to charge in to either meet the ball or create runner’s interference for an automatic out. Instead the ball trickled past Kieboom into center field, and two more runs scored. He wasn’t charged with an error. He was charged in the eighth on a chopper that nicked his glove and, had he caught it, may have led to an inning-ending double play. In the bottom half he struck out swinging to lower his average to .136.

“Baseball’s a crazy game,” Kieboom said. “You can be the man on the moon for a while, and then next thing you know you haven’t swung a bat before. So it’s all part of the game.”

He has the opportunity to play through this, at least for now, with the Nationals shorthanded and giving him a trial as their everyday shortstop. Kieboom was called up as an upgrade over Wilmer Difo, Turner’s initial replacement, and the Nationals will want to see how he handles this rut. He hit a month-long slump with the Class A Potomac Nationals last spring and responded with a standout summer. That will be harder to do against these pitchers — paid millions of dollars to get him out — but Kieboom has always found comfort in a steady routine.

And if last Thursday set his career in motion, maybe this one would set it on track.