Nah, it's actually normal for athlete to sometimes suck while adjusting to new training\game, in her interview Petra said that new training gives here more ability fitness wise and skill wise this means better results in tennis, also improving mentally but she still tend to fall to old habits which mess up whole thing. I think she just needs to play bunch of matches to get used to new rhythm, practice can't solve this, only real competition because people under pressure tend to forget their training
However, I feel this is all result (if you actually believe Petra, remember she has many excuses) of Petra playing Fed Cup.
Since Petra was sick, she should have taken those full 2-3 weeks after Istanbul to heal and feel better. So that way, she wouldn't have to recover after Fed Cup. I think this set her back, possibly 1-3 wks (coming back early to practice/play Fed Cup, the week she played, and the extra week to recuperate, after she played).
Remember, Petra wasn't even healthy when she was practicing for Fed Cup.
And if Petra knew she was getting a new fitness person, she could have used that extra 1-3 weeks for 2013 preparation. As it is, it appears that Petra didn't have enough time, for her usual end of season training (fitness and tennis), and I think that's one of the reasons why she's suffering now; or did the past few weeks. You can even say the same for Extraliga (another week).
When you only have a little more than a month before the new season, an extra 1-3 weeks preparation really makes a difference.