My iTunes says my ipod its full when its not
So I wanted to sync my ipod this morning to add 4 new songs. When I connected my ipod it said that there wasn't enough space which was weird because last time i checked i had 4GB left, anyways I decided to erase some songs so I can have more space, in total I erased about 4 or more albums. I connected again my ipod and it still said that there wasn't enough space, I tried to sync it anyways and it erased all of my songs. I desconected it and connected my ipod again and it said that I have 10.35GB in "others" but my ipod is empty! My whole itunes is 9.72GB and I have "left" 4.37GB. What is going on and what do I do???? Please help!! I'm desperate!
MacBook Pro, OS X Yosemite (10.10.1)