Have happily used my SLR

Question

Have happily used my SLR panasonic digital camera and taken thousands of photos on the SD card, but today it says "memory card error please check the card". Never seen that before and cannot access any of the photos on it. Can't see anything wrong with card, won't read in another panasonic camera either, nor through the card reader attached to my printer. Camera works fine with diferent card. How do I rescue my photos please?