So I went to play some more AC and... My XL stopped working.
When I went to the main menu to go to my friend list, the touch screen was unresponsive, as well as the Home, start, select, and shoulder buttons. Only the ABXY buttons work. I can't select any other program/game with the d-pad/circlepad. I couldn't even exit the game without pressing the A button.
Thank God I have the game cartridge, or I'd be out of luck.
I found a thread where someone had the same problem as me, though he has the digital version. I'm also trying the fix that the last person who posted suggested. Wish me luck. :/
http://techforums.nintendo.com/thread/25648