It sounds as if it's time to reset Spotlight. Read How to determine when your Spotlight index needs to be rebuilt. You can also use the appropriate version of OnyX. Go to the Parameters tab and select Misc. You'll be able to delete the Spotlight index from there and turn Spotlight on again.

Jon

macOS 11.7.10, iMac Retina 5K 27-inch, late 2014, 3.5 GHz Intel Core i5, 1 TB fusion drive, 16 GB RAM, Epson SureColor P600, Photoshop CC, Lightroom CC, MS Office 365