Help! Please help me ID what may be wrong with my plant.

[desertlzbn]

I have this problem plaguing my tomato plants. They get so big, then produce 2 or 3 fruit, then the leaves shrivel up and die, them the whole plant dies eventually. I don't know if this is a disease, fungus, bug, too much ferts, too little ferts, or what. I will attach as many pics as I can. I cut it open and the stem seemed ok. This happened to almost all of my plants this summer. The SWCs and my garden have had the same results. The other thing all the plants had wrong is the leaves don't grow much, they look stunted, and they don't get very big.