La Liga title challengers Atletico have lost three consecutive games over the past week, succumbing to defeat in both legs of their Copa del Rey semi-final against rivals Real Madrid and losing 2-0 in the league to Almeria.
Simeone's men will look to get back to winning ways against Real Valladolid on Saturday before travelling to face Milan in the last 16 of the UEFA Champions League next Wednesday.
Atletico remain level with league leaders Barcelona and Real in La Liga and Simeone is refusing to panic, despite the disappointing performances.
"Is it usual? (Atletico's poor form) No, but it happens," Simeone told Gazetta dello Sport. "Two were in the Copa del Rey against one of the strongest teams in the world.
"Am I concerned? No. Eight days ago we were first in La Liga. All teams sooner or later go through a difficult moment, let's see how we come out of it.
"If one looks at the 38 weeks of La Liga, it is impossible to think that we can compete with (Real) Madrid and Barcelona, impossible. They have a quality that makes a difference in the long run.
"Are we fatigued? Could be. Yet, if we talk of this then continuity was also one of the key factors to finding ourselves in this position.
"Nobody can guarantee that if we had played others then we would be in this position."
Atletico will take on a Milan side that sit a disappointing 11th in Serie A, but Simeone is still anticipating a stern test in the first leg at San Siro.
"Milan in the Champions League are much stronger than they are in Serie A," he added. "It is a question of the mind, the habit of playing for a big club that always wants to do well in Europe.
"Milan have many champions and should be approached with great humility, knowing that we will not be facing the team in Serie A, but a more aggressive one, with a great desire to do well."
