I planted these tomatoes a few weeks ago and they have been looking amazing until today. This morning they looked fine, but when I got home from work a few minutes ago I noticed that all of the plants have wilted lower leaves, except two! Can anyone identify whether this is a disease or just from improper care? Here is some recent history:

I had been keeping these babies under shop lights and started to harden them off. After they had seen a few full days of partial sun, it stormed for a two days and they went back under lights. I put them back out into partial sun yesterday and left them overnight. It got down to 44 degrees Fahrenheit last night, but the plants still looked great this morning. Only 6 hours later I returned home to find them looking rather unhealthy. Any suggestions?

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