Good news that you have your CDs as backup.
What I’m assuming is that, when you ripped your CDs (which initially are in a “generic” audio format, as distinct from computer formats such as MP3, aac, etc.), they got ripped into the format not compatible with the Clip.
At this point, your best (although time-consuming) option is to re-rip the CDs into a format compatible with the Clip, such as MP3 or flac. The next best would be to convert your current files to a Clip-compatible format; however, converting between compressed formats is “frowned upon,” because you lose more of the music’s data that way. Personally, I use the MP3 format with VBR (variable bit rate).
Regardless, it’s good to hear that you figured the issue out, and that your attitude is so positive! Once you set up a system now, you’ll be set for the future.