Game won't pause/fast forward, Sims keep moving, Infinite saving screen

Once I've been playing game for a couple minutes, the pause button stops actually pausing the game. "Paused" appears at the bottom of my screen as it should, but the usual red border when the game is paused is missing and my sims continue moving around. Once this happens, I am then unable to interact with any sims or objects. When I attempt to fast forward, sims still move and the game continues to run as if it were never paused. I tried opening and closing the gallery. I tried opening and closing the menu (with keyboard shortcuts and with my mouse), game options, etc. None of these work. When I clock "Save As..." the window pops up, but nothing appears other than the title and infinite loading symbol. When I click save, it appears to work, but then I get an indefinite saving screen and unsuccessful save, requiring me to force close my game (with Task Manager).