Well, to be perfectly fair, you didn't login for over a week. That means no training, no dealing with injuries, the same old formation every single game and so on. A drop in effectiveness is to be expected.
And for all we know, you may have simply faced more difficult opponents this week than before. It's not uncommon for people to play against the weaker teams in the league first, think they're unbeatable, then face opponents of equal or greater skill and wonder why they're not topping the charts anymore.