She basically didn't stop working from early 2000 til the end of summer 2002. There was only nine months between the end of Light Years single promo and Fever coming out. In between was the tour and recording the new album. She likely only got a couple of weeks off after the tour at most. The active Fever promo was constant - Kylie was doing all the TV shows on release weeks, then the planned break she had given herself before starting the Fever2002 tour was used to do US promo. In short, she was knackered.