I've been reading everyone else's postings, but this is my first one and boy, do I need help!

My big beautiful tomato plant has suddenly started dying from the ground up. It is one of those with an heirloom variety grafted onto hybrid roots.

"Spots" started appearing on the lower most leaves (see photos) - which quickly spread until the leaves turned entirely yellow and died. As the leaves die, the stems on those specific branches turn yellow, spreading toward the plant, but otherwise the stem and branches seem to be unmarked. The tomatoes themselves also seem to be unmarked, and are plentiful (looks like they started to grow before this infection got bad) but now that whatever it is is spreading rapidly up the plant, the new tiny baby tomatoes with the flowers still attached (and there are MANY of them) seem not to be growing (not sure yet if this is my imagination) and a few pollinated flowers (when I pull them apart after they fall there are baby tomatoes inside) are falling/have fallen off. Also, while the tomatoes seem to be unmarked, the little green "leaves" (I'm sorry for my ignorance - I couldn't find a name for them) attached to the top of the tomato show signs of dark speckling as well. It is spreading REALLY rapidly up the plant. I've attached a link with photos of all of these things too.

As I said, this is my first post and I hope this isn't too much information! But from looking at others' posts it appears that many tomato diseases have somewhat similar characteristics so I was hoping this would help one of you more experienced guys with identification.

Any help would be greatly, greatly appreciated!

Your fruit looks great!