We could be starving, we could be homeless ... we could be puking? Justin Bieber kicked off his Believe tour in Arizona Saturday night, but the 18-year-old was apparently a little sick. Bieber vomited twice while on stage, but he didn't cancel the show. About halfway through the concert, Bieber turned his back to the crowd and threw up before running off the stage. A few songs later, he had to run off again. He apologized and asked the crowd, "Will you love me even though I'm throwing up on stage?" He later tweeted that he shouldn't have had milk before the show.