Barca have now gone three games without a LaLiga win having picked up five points out of a possible 21, suffering defeats by Leganes and Las Palmas in their previous two home games. They are three points behind Atletico having played a game more.
Despite their first home defeat against Atletico in 18 years, Flick said they put on a good performance and expected the winter break to help them regain their early season form.
"Today it was unbelievable how we played. Maybe this break came at the right time. I appreciate how we played. But we have to learn from these things. Losing nine points is not normal and we have to work on it," Flick told reporters.
"The points lost against Las Palmas and Leganes are in the past. We will show after the break how strong we are. We are very disappointed with the defeat, but life goes on."
In spite of their latest setbacks, the former Bayern Munich coach said he was proud of his young team and will work to restore their confidence.
"When I drive at 06:30 to go to training I am happy because I can train with these players. Now there is not a good atmosphere in the dressing room, but that's football. We will be back for sure," he said.
"We have to build confidence and make them proud of how they play. My job is to give confidence to all the players. In Munich there was another team with a lot of experienced players. But I'm happy with this team, it's young and has fantastic quality."
