I think he fell off the wagon big time with all the stress over the Passion. After that movie, he was acting pretty nuts (well even more nuts)and seemed to age about 20 years which I suspect is from the booze. Also, a big side effect from alcoholism is self destruction which may be the reason for his comments. It all becomes about the booze after a while, and if the career or job gets in the way of that, you destroy it, conciously or subconciously, so you will have more time to drink (take it from one who knows). I mean what is the WORST possible thing he could have said to screw up his career? Mel has a huge booze problem, and to me that is the reason he said "My life is f****d." Now it probably really is because they taped everything he said.
I am one who knows as well. I believe your observation is spot on. And, like you, when I read "I'm F**KED, the first thing I thought of was that he wasn't talking about his career, he was talking about his family. If it's all out in the open...well...you know.