Barca are 11 points clear in La Liga but face an early Champions League exit to AC Milan and were dumped out of the King's Cup and beaten in the league by Real Madrid last week.
The prolonged absence of coach Tito Vilanova, who is recovering from cancer surgery in New York, has been an unwelcome disruption but Mascherano dismissed talk of a crisis.
"This is a very dynamic sport," he told a post-training news conference on Tuesday. "Three weeks ago it looked like Madrid were going down in flames and now everything is fine."
"And a few weeks ago this place was Disney and now apparently it is the House of Horrors."
Barcelona host Milan in their Champions League last 16, second leg next Tuesday needing to overturn a 2-0 deficit from the first leg at the San Siro.
Their recent performances have been marked by a lack of dynamism in attack and an uncharacteristic sloppiness in defence and Mascherano said the players needed to step up their efforts.
"We haven't been doing justice to what this team can do and we need to get our game back," he said.
"We don't have to go crazy, we just have to have the serenity and humility to find what we're missing and from there go back to being the team we were a few weeks ago.
"Sometimes the results just don't come and it feels like it's all caving in. But as long as we stay calm, we'll get through this.
"The best way to lift ourselves is to think about what we've got left. We have to think positively. The only way to improve is by working hard and having a positive, winning mentality."
Mascherano also defended his compatriot Lionel Messi, who has been accused of failing Barca when they need him most.
The World Player of the Year barely mustered a shot in Milan and was largely anonymous in the King's Cup semi-final second leg against Real, although he did score his 39th league goal of the season in Saturday's 2-1 defeat at the Bernabeu.
"Messi is judged because in the last five games he's scored three goals, not ten," Mascherano said.
"It is very easy to only analyse the last fortnight rather than the last five years.
"If anybody doubts the system, this club's ideas, they should look back at the last five years and that should clear up any doubts."