Van Gaal's appointment was greeted with great fanfare at Old Trafford, but after 10 matches United are 10th in the Barclays Premier League.
"It's not good enough," the United boss said when asked to evaluate his team's start to the season.
"I feel lousy."
Van Gaal has garnered just 13 points so far even though United had a favourable run of fixtures at the start of the season.
His predecessor David Moyes, who lasted just 10 months in the job, had 17 points at this stage last season.
Van Gaal added: "I feel, myself, very lousy for the fans firstly, but also for the board because they have a great belief in me and my players and my staff and when you have 13 points out of 10 matches you are not doing well."
Source : PA
Source: PA