Roberto Martinez’s side have slipped to sixth place in the Premier League, after suffering a 1-0 defeat to nearest rivals Tottenham.
The result leaves the Toffees five points behind Liverpool in the fourth and final Champions League spot.
On-loan Chelsea striker Romelu Lukaku is currently sidelined with an ankle injury, which has left Martinez forced to play natural wide man Kevin Mirallas as a striker.
January loan signing Lacina Traore is still getting up to full fitness, while the club sold Nikica Jelavic to Hull City during the transfer window.
“We’re struggling a little bit at the moment,” Jagielka told the Liverpool Echo.
“Lacina is not quite right yet and it’s difficult because although we played some good stuff, we were perhaps missing that fox in the box or target man to get us the goal.
“It’s frustrating and, at the least, we should probably have kept a clean sheet and come away with 0-0 but we didn’t.”
There was some good news for Martinez on Sunday however, as Spanish winger Gerard Deulofeu returned to the first team fold after injury.
“I am really, really happy to be back. I have been doing my rehab in Barcelona but I am happy to be back at Everton,” Deulofeu said.
“My leg felt great, absolutely perfect. I have been working around the clock to get fit and get strength back in the leg. The main thing now is to keep working hard so I don’t get any relapse.”