Crash on save file load

This all started when the game started being really choppy.  I started the campaign mission Lambs to the Slaughter, and I started using Prophecy to scout the map.  About 3 minutes in the game became unplayably laggy, and so I saved the game and tried to load, hoping that would fix it.  Upon load, the game crashed.  Before it crashed, the game caused both of my monitors to flicker off upon which it resized itself big enough to fill my second monitor (the game is supposed to be set to windowed mode at 1920x1080 resolution, and my second monitor's resolution is set to 2560x1440). After I clicked okay on the crash report hidden behind the game, I waited for steam to finish closing the game, then tried to start it again.  When it was loading, it was again filling the screen of my second monitor.  After waiting for a while, the game still was a white screen, so I gave up and closed it. Again, when I tried to start it again, it was filling my second monitor, then after a short time it shrinked back to the normal size.  However, the choppiness still won't go away while the game is focused (it shows fine when it is not the focused window), and whenever I try to load the save file I made, the previous things I mentioned about the expanding game window and crashing repeat themselves.