Oh, poor Sadie! Is there anything going in the house, a new project, construction that might cause her to sneeze? Have you changed her diet/bedding? Are there any other symptoms, like coughing, a runny nose? She might have a cold/virus or maybe she's developing allergies or it might just be dry air or dust that's irritating her nasal passages. If she's still sneezing tomorrow, I'd call the vet to get checked out. Please give her a big, big hug for me Sarah. Get well soon, sweet Sadie!