I'm looking for a short story I read probably 15-17 years ago, although it might have been written long before that. I only remember it vaguely, but it stuck with me.
It's about a man who can see what he'll be doing one year to the day in his future, so he knows how his life is going to turn out before it does. The chilling/memorable part is when he sees his own death, and then over the next year experiences being buried and then the slow decay of his higher mental functions as his brain breaks down. I think it's described as first having the capacity of an animal, then a plant, then only inanimate rock, or something like that. It ends with his actual death.
I remember it as being scary but I was very young when I read it! I think it was in an anthology of science fiction stories, although I'm not certain about that.
Any help would be appreciated!