Is my tarantula sick or is she about to molt?

I have a rose haired tarantula and lately shes been acting weird. A few nights ago i noticed her abdomen had shrinked and i did some research but none of the answers made sense because it said her abdomen would shrink if she was dehydrated but shes been drinking water and eating. yesterday i noticed something else she isnt moving alot and shes been dragging her 5th pair of legs but she walks perfectly fine with her other legs. Im really worried that she might be sick so does anyone know whats going on with my baby? :(