Tito Villanova's side suffered back-to-back defeats to rivals Real Madrid and they were beaten 2-0 away to AC Milan in the Champions League two weeks ago.
They still remain 11 points clear at the top of La Liga, but Mascherano has admitted there is still a lot of work to be done.
He told AS: "Three weeks ago it seemed like this was a Disney film but now it feels like a horror show.
"Three weeks ago Madrid were in crisis and now everything is great for them. We have to recover our style of play if we are to get good results again.
"You are obviously not in a good way when you have one or two weeks of bad results, especially when you get knocked out of the Copa del Rey and lose the Clasico, but we cannot dwell on that."
The Argentine added: "The best way of lifting ourselves is to think about everything that is still to come this season and to try and be positive. We have to improve in many areas and the only way to do that is by working hard.
"We all have to give more to get out of this bad run of results, although there is no need to go crazy either.
"We have to remain calm and be humble to find out what has been going wrong and be the same team we were three weeks ago. We all have to give a little more, we're in an unusual situation.
"If anyone has doubts about this club, go look at the statistics from the last few years. It is easy to say there is a problem here but these situations make you stronger.
"Success, as one coach has said, changes you, it makes you feel that you are better than you really are and these situations make you feel stronger."