Edges were smooth but now they're rough

I was working last night on a graphic, creating a shape with the polygon tool and paint-bucket-filling with straight black. Saved work and today continued my work. But now when I make polygon shapes and paint-bucket-fill, the edges are super gagged. Modifying the selection to feather actually makes it much worse. Does anyone know what is going on? I've actually seem this problem before, but don't recall if I did anything to fix it. I've attached a screenshot.