The German, 21 points adrift of Mercedes team-mate and double champion Lewis Hamilton as the season enters its second half, spent the August break at home preparing for the arrival of his first child.
His wife Vivian is due to give birth to a daughter next week and Rosberg said he had the family cars ready for the trip to the hospital.
“Everything's packed, the car engine was running in the garage,” he smiled in a meeting with reporters at the Belgian Grand Prix.
“The baby seat is in the Mercedes ML and it took me two hours to put it in there,” he added. “It was one of the toughest recent experiences.”
The pain of Hungary, a topsy turvy race where at one point Rosberg looked like emerging in the lead of the championship but ended up eighth and further behind Hamilton after a late collision with Australian Daniel Ricciardo, had eased.
“Hungary was very annoying because it was such a great opportunity to close the gap on Lewis,” he said. “It's also just annoying to lose second place in such a way right at the end there.
“So it was tough but as always in sport it's not very long lasting, those emotions. I did very much enjoy the summer break.”
Faded also were the memories of last year's Belgian Grand Prix, where the two Mercedes drivers collided on the second lap of the race in a drama that led Hamilton to accuse then-championship leader Rosberg of doing it deliberately.
“It was a tough time after this race here for everybody but no regrets. I learned a lot. That's it,” he said.
Hamilton has won five races to Rosberg's three this season but started nine of 10 from pole position - a reversal of last year where the German was the qualifying king in a battle that went down to the wire.
“I need to keep pushing the way I have,” said Rosberg. “It just needs to be slightly the other way and that's it. It's 21 points and at times in the last race I was actually leading the championship.
“It was very close in the first half (of the season) and with sport it can go either way...I need to keep pushing, keep winning races and I believe I can make it happen.”
Original source: Rosberg's car trouble? A baby seat