SD card filling up for no reason

My SD card had about 20mb left, and I could listen to music and take pictures no problem, but when I started using tumblr again on my phone, my SD card in the settings said that it was completely full, and now I can’t access my music; deleting music and pictures doesn’t seem to be doing anything. This is on a Samsung galaxy ace. Please help

Probably the wrong board for this question. :wink: