Stuck in Black-and-White Mode

I was working on an Illustrator file when the colors suddenly vanished. Everything displays in black-and-white. If I copy a layer and paste into a document, it looks fine, but I can't fix the original.

I Google'd for help and tried setting my document to RGB, only to discover that it's already set at RGB. I also saw a reference to "Color" in the menu, but I can't find it.

Another thing that's changed: I just learned how to use the envelope function. I have some red text inside a circle. In my document, the text is now black-and-white, plus the text isn't warped; it's just plain text. Again, if I paste it into a new document, it restores the red warped text.

Does anyone know how I can fix this?

Thanks.