Please try the following:
Delete Pillow from your Apple Watch
Restart both the iPhone and the Apple Watch
Flip off & then on again the Motion & Fitness switch for Pillow
Re-install Pillow on your Watch
Please try the following:
Delete Pillow from your Apple Watch
Restart both the iPhone and the Apple Watch
Flip off & then on again the Motion & Fitness switch for Pillow
Re-install Pillow on your Watch