What's been keeping Janet Jackson from honoring her tour commitments? Her rep says she's been having vestibular migraines, which cause vertigo. "[Janet is] a world-class entertainer and needs to be at the top of her game to give her fans the show they expect," manager Kenneth Crear said in the statement. "She's feeling much better and is ready to hit the road again." She's scheduled to finally resume her tour in DC tonight. [People]