Earlier today, we posted you the video of Madonna collapsing on stage while performing in Bulgaria last night. The shocking scenes prompted a media frenzy over the state of her health, as the 51-year-old pushes herself to the limit on her Sticky And Sweet tour. Now a source close to the star has revealed the real reason behind her fall. The insider says, “It turns out she's suffering from exhaustion. She is anaemic. She was advised to postpone the last two shows in Israel for a few days, but logistics and stubbornness stopped her. She'll do them then take some rest." However, news reaches us that Madge is set to start training for a gruelling six-day, 151-mile marathon in Morocco next April as soon as the tour finishes. Altogether now: “If you took that hooo-liday, it would be-ee, it would be so nice.”