Well, it's probably not "all of the sudden" -- you mention there were a bunch of periods that you could have gotten away with it. That makes me think it's been in your mind all along. It's a mental obsession. It's always on, even when you're not aware of it, always plotting for a moment that might "work". It seemingly has stumbled on one now and has ramped up it's efforts to get what it wants.
Advice? I got the point where my obsession won. I was toast. I had had to be honest with everyone and get help. It's everywhere you look, believe it or not.