It sounds like there's some sort of issue with your card. I'd recommend that you try accessing it via Linux Live CD/USB, to see if it is properly recognized and if you can get to your data, or try some of the data recovery programs from this thread: http/www.tomshardware.co.uk/forum/id-1644496/lost-data-recovery.html
If your phone is recognizing some of the files, I'd recommend that you connect the phone to your computer and back them up if you can.
It sounds like there's some sort of issue with your card. I'd recommend that you try accessing it via Linux Live CD/USB, to see if it is properly recognized and if you can get to your data, or try some of the data recovery programs from this thread: http/www.tomshardware.co.uk/forum/id-1644496/lost-data-recovery.html
If your phone is recognizing some of the files, I'd recommend that you connect the phone to your computer and back them up if you can.