I have no idea how to describe my problem and no idea why it happened. I just rebooted and for whatever reason my desktop changed. I'm extremely new to Linux (less than 2 weeks total) so just keep that in mind while responding please. I heard it might be an issue with Gnome? It's not just my desktop either, everything looks different. It feels like an entirely different distro.
What my desktop looks like before I rebooted (picture off of Google):
What my desktop looks like after I rebooted:
[EDIT] I've been using Ubuntu 17.10 with no problems for the past couple of weeks. It's the only OS installed on my system; I am not booting from a USB.