City go to Liverpool on Sunday having lost five consecutive games before blowing a 3-0 lead to draw 3-3 with Champions League opponents Feyenoord at the Etihad.
"Of course it's not nice but what do you expect? That everything is red carpet? That everything is nice and easy?" he said.
"It's easy when you are (winning) 10, 12 games in a row, everyone is fit, everyone is in their prime and everyone is 26, 27, 28. When everything is going well, that is easy.
"I have to prove myself now.
"In long careers - nine, 10, 11 years - you live all the situations.
"We lost five games, drew the last one when we should have won, but it happens in football sometimes.
"(I have to) accept it. No complaining, no blaming, no pointing. Don't run away from your responsibility. I have absolutely all on my shoulders. I have it and I want it.
"At this football club you have to win. If you don't, you will be in trouble. I know the people say 'why is Pep not in trouble, why is Pep not sacked?' I have this margin because of what we have done over the last eight years. The people rely on me.
"What's for sure is I want to stay. But the moment I feel I am not positive for the club another one will come.
"In a decade of time, we have been here," he said. "Tell me which team around the world has been as consistent in 10 years... It doesn’t exist. Not in NBA, not in tennis, not in golf, not in any sports."
Guardiola also said: "We will be back, I know that. I don't know when.
"In the situation we are in, it is not realistic to think about big targets. The situation is to think about the next game and what I can do to help the players.
"I don't want to run. I asked for this opportunity. I want to be there and rebuild the team in many aspects from now on until the end of the season and next season."