I have three tomatoes in a line, all good and strong in good compost. I water at night (no sun) but we have had so much rain. I fed them the other night and now the one that makes big tomatoes but leaves are badly drooping! I so hope I’ve not killed it. The other two seem fine…fingers crossed. I’ve not over fed them as I’ve read the bottle. Should I keep watering? The leaves are not going yellow “yet,” they’re just drooping not like the other two which seem fine.
It certainly doesn't sound like your plants are suffering from lack of water (the most common cause of tomato plant wilt) since you said you've gotten so much rain.
This leaves fungal disease or bacterial wilt as other possible causes, especially since two of your three plants are fine.
This article may help you, and also provides links to additional information about fungal diseases and wilt: https://www.gardeningknowhow.com/edible/vegetables/tomato/wilting-tomato-plants.htm