Really?
I'm losing 7M a month!
I would try getting in touch with SI and upload your save in the bugs forum. In previous editions, they have been able to " fix" broken saves although in most of those cases, the problem was crashes etc so I am not sure they can here. Mind you, unless you have used an ingame editor, it might be worth trying.
This seems to have happened to a lot of people but SI have yet to get their hands on a save with the bug so if you have one before this happened, if you post it on their bugs forum, they will stick a chance of fixing it.