I feel for you, Lisa B. I've had years like that - last year was one of them, when I had record rainfall, until around 7-20, when we went into a drought. If your future forecast is getting dry, you may be able to do something; otherwise, if the wetness keeps up, which I assume you've been getting, to cause this fungus, there's not much you can do.
Last year, when it got dry, I trimmed as much as I could from the plants, then sprayed the remaining parts of the plants with copper soap - something I seldom use (only when absolutely necessary, when it might help,, but it will kill what is on the leaves. Very quickly, the plants grew new growth, and flowered, and I got a generous amount of tomatoes later in the season.
If it is going continue to be rainy there, you can try another application, as long as it won't be getting over 90° for several days after application: an oil and baking soda spray - 1 tb baking soda + 4 tb oil to a gallon of water, plus an emulsifier, like soap or ThermX 70. If you use potassium bicarbonate you can add up to 3 tb. - that's too much sodium, but potassium is a fertilizer! And you can apply some higher amount, without the oil, at higher temps, as long as it's not sunny, as well. I use the potassium bicarbonate (food grade KHCO3 can be bought on Amazon, much cheaper than the gardening brands) as a prophylactic on the tomatoes and cucurbits, though it didn't do anything last season, because it wouldn't stay long! The main thing with any spray is to cover the tops and undersides of the leaves.
Good luck getting this under control!