In 30 hours of gameplay I had probably 2 crashes. However, now my game freezes at the loading screen every time. The thing is, though, it didn't happen after a crash so i don't think it's corrupt. I hadn't had a crash in several hours of gameplay time (not several hours at once, spread out over the week) and then I decided to play one afternoon and it freezes at the loading screen every time after I select continue. Any ideas? Or do I just have to start over?

Well first don't select continue go to load and manually pick the save. The last time the game froze was it around the time the game would autosave? In a few games with autosaves I've had it freeze right at that moment which corrupts the autosave as your forced to restart the system.
Check your savedata utility and make sure the save i still there. I suspect you'll find an icon reading corrupted data. This has happened to be in Oblivion, Fallout 3 and Grand Theft Auto IV.[its a flaw in the entire system of autosaving.]

You may be able to salvage the save by booting in "safe mode" and picking restore file system. This link explains the recovery menu and how to access it. http://boardsus.playstation.com/t5/PlayStation-3-General/How-to-access-the-PlayStation-3-Recovery-Menu/m-p/39144801
However if your save is corrupt to the point it won't even load I doubt anything can save it.

Auto save is disabled and there wasn't a crash prior to the problem. I'll check the save file any way, though.