Page isn't centered. Send help.

I took multiple projects from my google docs account and began the painstaking job of copying them over into my Scrivener software converting it all into a navigable mess. But after I did that it completely screwed the margins. Now when I fullscreen my project (I like fullscreen for reading through looking for mistakes) its completely on the left side.

I pulled up the ruler to adjust the margins, but anything I try just makes it worse. Please help, it is a HEADACHE to read like this