The camera's view is grey/grayed and I can't see anything out of the camera's sight? So everything out of the camera's sight is invisible and it's there's this grey/gray (I don't know how it's spelled) thing highlighting what can be seen. What's going on and how do I fix this? I need to use assets that are out of my view. :(
Seems like you are in 'clipping' mode. Simply press Alt+B and you should be good.