I have a drawing that I've been working on for a while now and today when I went to open it and work on it, it opened blank. All of the layers were there and the name of the file was correct, but everything was blank. How can I fix this? Do I have do everything all over again?

If all layers are there, and the layer thumbs show content, then your file is not corrupted. Try toggling the visibility of some layers, or switching opengl off.