Justin Bieber, 24, is going through a tough time as his relationship with Selena Gomez, 25, is on pause. Selena is currently on vacation with friends in Sydney where she appears to be carefree. However, a source reveals that the same can’t be said for Bieber. “Justin has Selena on the brain constantly. He is trying to drown it out by hanging with friends and doing stuff on his own time but he keeps thinking about her,” a source tells HollywoodLife.com. “He always wants to be around her, talk to her and be with her. She is like a drug for him, he just needs more and more and more.”