Fulham, whose last home win in the top flight was against QPR on April 1, failed to follow up the Capital One Cup defeat of Everton by defeating Cardiff, as the Welshmen claimed their maiden Premier League away win with a 2-1 success.
Jol, whose contract expires at the end of this season, guided Fulham to ninth and 12th-placed finishes in his first two campaigns, but his side are now in the relegation zone.
The Dutchman said: "We have to do better, but I can't go on the pitch and do it myself.
"We beat (Everton), but it's the Capital One Cup, it's not the Premier League. And in the Barclays Premier League you have to win your games.
"Everyone who is in the bottom three or bottom five is concerned. There's always pressure.
"I take responsibility, because I took all these players on board.
"It was not easy, because we don't have all the millions but I still feel that we did well to get the (Darren) Bents, even (Dimitar) Berbatov. (But) it's not good enough to win games sometimes.
"It's not about me. If you're in the bottom three or four you're under pressure. I try to make people happy and most of the time I've done that."