Jaz64 Hi! Sorry for the late reply, did you manage to recover your files from the SD card? If not, we actually have a guide on what to do when a SD card asks to be formatted, it might be worth checking out.
In short, first you should check if the SD card shows up in Disk Management(Windows)/Disk Utility(Mac), and see if the reported size looks correct. If it does, the next step would be to create a full image of the card and then scan that image with a data recovery tool like Disk Drill (or any other reliable memory card recovery software) and recover the files to a different storage device. Once your data is safe, you can try to fix the card or simply format it and keep using it.