Impacted?

Hey all, been a while since I was last on here

So...my Nile Monitor has been doing pretty well over the winter here, then last week she started being extremely lethargic and her appetite all but stopped completely. Now I figured this was kinda normal since it was winter (though I was still keeping the temperatures up). She started smelling very badly though, and after a few days she defecated what looked to be a mixture of liquid feces and sand, and she's done that now a few times, with the stool becoming consistently more solid each time. Is she perhaps passing an impaction? She was on a sand substrate before I adopted her, and I'd seen her eat mealworms right off the sand bedding before.