Does tomato wilt affect other plants? Can you eat the fruit off the tomatoes plants?

We have huge plants, in a small garden space. My tomatoes are showing signs of wilt, but perk up after rain. I noticed my cubers and some of my yellow squash and zucchini are not growing after they form and begin to rot. Can I save my plants? My herbs in the same small bed are doing great. What can I do to prevent this from returning next year. (already know about purchasing resistant tomatoe plants, but what else??)