LORELAI: I don’t know. It’s weird, Sookie must be sick or something.
RORY: Sookie never gets sick.
In fact, Sookie said that she had a little bug the week before. Later events suggest this may have been morning sickness, since we never learn exactly what this “bug” entailed. Although only a scriptwriter who has never been pregnant would think of morning sickness as a “little bug”, so I don’t know.