However, Lambert insists that it is his job to keep the spirits of his players up for the final few weeks of the season.
"I will not get downbeat. It hurts like hell to lose, of course, but I will keep the lads upbeat," the Scot told the club's official website.
"You keep going. We're still a few points above it. And now we try to win the next game. Getting the win in the next game gives you that breathing space.
"I always believe we can win. I never waiver from my belief in the lads. I am positive."
Villa resume their Premier League duties on Saturday at home to Southampton.