I fixed it!
I'll go through what I did in case some other new user could use the information:
I'm unfamiliar with grub, so I googled how access it (hold shift after BIOS pages load) and then did so. I entered the advanced options menu, selected recovery mode, and it brought me to this message:
/dev/sda1 contains a file system with errors, check forced.
Inodes that were part of a corrupted orphan linked list found.
/dev/sda1: UNEXPECTED INCONSISTENCY; RUN fsck MANUALLY.
(i.e., without -a or -p options)
fsck exited with status code 4
The root filesystem on /dev/sda1 requires a manual fsck
BusyBox v1.22.1 (Ubuntu 1:1.22.0-15ubuntu1) built-in shell (ash)
Enter 'help' for a list of built-in commands.
I wasn't sure how to run fsck manually, so I hopped back on my usb and googled it. I booted back into the recovery mode, and I ran: fsck /dev/sda1
Every time it found a corrupt file and asked if it should fix it, I said yes.
When it was done, it brought me to a new screen with a list of options, such as using dpkg to fix broken packages. This is the only option I used. After that I booted back into my usual GUI. I needed to reboot again for my graphics card to turn on (and thus fix the resolution).
This is probably such an obvious thing, but after using windows and mac all the time--you know.
Good luck from a huge noob!