MY CAMERA says memory card error?

my camera is a canon powershot sd 750. ive been using the same sd card in this same camera for 4 years. all of a sudden i uploaded some pics, put it back in my camera and it says memory card error as soon as i turn on the camera. when i go look at my pics it says the same thing and at the bottom it also says memory... show more my camera is a canon powershot sd 750. ive been using the same sd card in this same camera for 4 years. all of a sudden i uploaded some pics, put it back in my camera and it says memory card error as soon as i turn on the camera. when i go look at my pics it says the same thing and at the bottom it also says memory card locked. i am leaving for cali tomorrow morning and need help I have no money to download anything. And i shouldnt have to. I didnt do anything to the stupid sd card. life just hates me can you please help thank you