Doom 3 dosen't run in Widescreen anymore

Last week i was running with the settings in which i always i run it at: 1152x864 (or something like that) at high settings. Today, a week later (i haven't touched the game at all) the game starts running really slow when i load it up plus it's not in widescreen. So i go to options and the game is at the same settings as in last week, but it's really slow and not in widescreen! so i changed the settings around and then i put it back at the regular settings. Now it's not slow anymore but it's still not widescreen! Why isn't it widescreen anymore?!

Thanks.