Zidane, who has guided Madrid to two Champions League titles and a LaLiga crown, is under some pressure at the Santiago Bernabeu.
Madrid have fallen 16 points behind leaders and rivals Barcelona after winning nine of 17 league games.
Zidane, who has been in charge since January 2016, said he understood he would have limited time at the helm of Madrid.
"Zinedine Zidane isn't a player at Real Madrid anymore. That Zidane no longer exists," he told France Football.
"Now it's down to Zinedine Zidane the coach to carve out a career. I'm not protected by what I've done as a player at this club.
"I know that one day it [the coach's job] will come to an end at Real Madrid, so I make the most of it and I do everything I can to be successful.
"I say to myself, 'if I've got 10 days left here, then I'm going to live those 10 days to the max; if it's six months, I'll live those six months to the max'. I don't think beyond that.
"I know I won't stay [in the job] for 10 years."
Madrid are yet to hit top form in La Liga, failing to win three of their past four league games to be fourth in the table.
But Zidane, who won La Liga and the Champions League as a player with Madrid, said his ability to ignore any outside pressure was crucial.
"External pressure doesn't affect me. I've wrapped a shield around myself; nothing can bother me," he said.
"I have many responsibilities [as Real Madrid coach]. But when I get home, I switch off. I know that many coaches aren't able to take their minds off the job, but I do have that ability.
"I go home and I get together with my wife or with my sons and I go to see a show or to have dinner. I cut myself off [from work], because that's fundamental."