Guardiola's men head into Saturday's clash with Borussia Dortmund 10 points clear at the top of the Bundesliga.
The Bavarians also have a DFB-Pokal quarter-final meeting with Bayer Leverkusen and a UEFA Champions League last-eight tie with Porto on the horizon this month.
However, Bayern have plenty of problems ahead of the trip to Signal Iduna Park. David Alaba is out with knee ligament damage, while Franck Ribery, Arjen Robben and Javi Martinez are also on the sidelines.
And, with speculation mounting over Jerome Boateng's private life, Bayern's preparation for the fixture could certainly have been better.
Guardiola said: "This month is a big challenge. I'm motivated. I know that it is not easy, we have many major problems.
"I must speak with the players. We can do this. It is my most difficult phase since I've been here. Because it is the most important stage of the season. I was never looking for an excuse. I have much faith in my players.
"We want to fight for all competitions. But without David, Frank, Arjen and Javi, we are not as strong. When all are fit, we are strong.
"Nevertheless, there are no excuses. If we don't win, we're to blame."
Turning his attention to the issue of Boateng, Guardiola added: "He has trained well. He is okay."
