Colors suddenly changed - red & blue turned gray

Hello all,

I must've hit the wrong keystroke, because suddenly my page, which has text and several images, has gone strange.

Red text -- and any portions of photos that have red or blue in them -- have turned gray or partly gray.

It's probably a simple fix, but I went back and hit "undo" as far back as I could, and no luck.

Anyone know what I might have done?

Thanks so much,

-S

PS: It's not set to Grayscale, but RGB. And no other colors are affected - not yellow, not a lighter red or blue or magenta or green - just the primary color range of red and blue. In a photo of a red jacket, a swath of the red has turned gray, but not the rest of the red jacket.