Jon Stead's spectacular overhead kick a minute into the second half gave Town a deserved victory and left third-placed Reading with only one win from their last eight games.
It was also the sixth game in a row they had fallen behind and they have scored just two goals in their last five home games.
Coppell said: "I'm joining a very limited club and am proud to be doing so. I suppose I must have done something right but whatever I was doing right I'm not doing at the moment.
"A manager's longevity depends on results so if I don't liven up I'm fully aware of the consequences.
"It's painful. I feel for the fans and I feel for the players because they are trying.
"From February onwards we have been less than average at home. We have nine games to go, six are away and at this stage of the season it is harder for home teams.
"But that is no excuse - we know we are not performing to our potential at the moment. We are not playing well enough to win games."
Ipswich have also been hampered by poor home form but manager Jim Magilton knows his players can compete with anyone in the Championship as they had drawn at leaders Wolves in midweek.
He said: "We have gone to Molineux and the Madejski and taken four points so I can't praise my players enough for their commitment, work ethic, attitude and application to their roles.
"I'm very proud of them. They have been absolutely fantastic. We've still got a chance of making the play-offs."
Reading had started brightly and Dave Kitson, making his second Royals debut after returning on loan from Stoke, headed against the bar after just four minutes.
But Ipswich weathered that early storm and were by far the better side after Stead netted his 10th goal of the season in spectacular style.
Magilton said: "It was a training ground goal - not. He's our top scorer and has had real moments for us. You have got to show belief in Jon and if you do you will get more performances like that.
"He hasn't always played well for us but he did."
Ben Thatcher cleared Michael Duberry's header off the line but Reading rarely threatened an equaliser to fall further behind Wolves and second-placed Birmingham, with Sheffield United now only a point behind.