Jessica Simpson is on top of the world. Six months after announcing her separation from husband Eric Johnson, the singer "has a new sense of confidence and is coming back into her own," a source exclusively tells Us Weekly. "She's doing well since the split," the insider says. "She's a different person since she's been out of the relationship." The 10-year marriage was "holding her down," according to the source, who says Simpson, 45, "wasn't happy for a long time" due to "trust and communication issues" that "just got bigger.