So whats with demi lavato?

so demi lavato was a big thing but then she disappeared she was in sunny with a chance for like 3 years and then disappeared but the weird thing is shes not in the new disney show so random which came outt of the show sunny with a chance and no new music came outt from her besides that new song skyscr which her voice sounds so weird like if she hasnt been singing for a long time sounds sorta crakey so someone tell me please what happened to her??!