Klopp's side saw their top four hopes take a hit on Monday night as champions Leicester outfought the Reds to secure a 3-1 victory at King Power Stadium.
Liverpool have now won just two of their 12 matches in all competitions in 2017, and host Arsenal at Anfield in Saturday's late kick-off with Champions League qualification on the line.
Klopp enjoyed a remarkable 4-3 victory at Emirates Stadium in his first ever Premier League game on the opening day of the system, but admits that his side can no longer ignore their problems as they battle to achieve their goals.
"It doesn't feel that free-flowing any more. We have this lack of consistency, we cannot ignore it," he said.
"I am not a clown - even though a few people think I am. I am not always laughing like crazy, I am a normal person.
"It is not about laughing the whole week and ignoring the problems you have.
"We cannot ignore the things that happen around us but I am 100 per cent optimistic again when I think about the Arsenal game - but I cannot say I am in exactly the same mood as the start of the season."
Klopp disagreed with the suggestion that defeat at Leicester highlighted his players' lack of fight, saying: "I think we are usually clean - not ugly challenges - but physical. It is not a general problem for us.
"Sometimes you need tactical fouls but being harder than allowed I don't think it makes sense. I never force my players to make fouls.
"We are always a pretty fair team as even in a challenge we want to keep the ball and not break a leg.
"Being physical means being ready to hurt yourself not the other player."
Asked about potential reasons for Liverpool's dramatic loss of form this calendar year, Klopp said: "When I was involved as a player I was a real mentality player and my strength was pushing a few team-mates, but for me it was not always possible.
"We have players who do it in different ways. Adam (Lallana), Milly (James Milner), Lucas Leiva are three players for sure.
"When you play bad this question always comes up but when you win no-one asks 'Who pushes the team?'. That was not the reason for not performing (at Leicester)."
A lack of depth in the squad has also hampered Klopp, with striker Daniel Sturridge likely to be out for at least another week after sustaining a hip muscle strain immediately after recovering from a virus.
"I can't ignore the game against Tottenham (a 2-0 win) with pretty much the same players who did really well," added the Reds boss.
"Should we doubt them in general? I don't think so but we have to react and we have to deliver each week.
"Being consistent is the most important thing when you have the quality to reach something.
"If you win it is easier to change things than if you lose, because if I change four or five positions then I take them out of the responsibility and put it on the shoulders of other players."
Additional reporting by the Press Association.