If it happens again, try deleting your cache files (as many as five depending on what EPs you have) - I get load freezes like this on a somewhat regular basis and it usually only takes deleting the cache files to solve the problem. Also check your "current game" folder after any game crash or force quit - this folder should be empty if your game shut down properly but if you've had a crash, files will remain and logic suggest that they could conflict with the loading process.
Although the fact that you were loading a new EP and were having some CC issues at the time likely means it was something else.