automatic update 4.3.1 ruined my websites, Neutica

Hi, Im a wordpress user, not a programmer, and spend a fair amount of time creating my websites w. wordpress, and, until recently, appreciated the open forum and collaborative efforts of the many creators
BUT
around 6 weeks ago I realized that my websites, the lay out, had been ruined by en auto update to 4.3.1
to me, that was devastating, I could not find a way to restore to an older version of WordPress, and I never approved the auto update function.
The fact that an auto update could ruin all my sites, the presentations of my professional activities and income generated from them, seemed impossible…

So, please, dear creators and programmers who know more than me…
I tried the only advice that seemed do-able, disabled plugins one after the other, it didn’t help.
my site are/were on the theme Neutica+, that I liked, and spend a lot of time adjusting to my purpose. this theme is no longer being updated.

any good advice for restoring the site? if it can not be fixed, can anyone recommend a different way of using Word press, so it will never happen again!!!

I saw in the forums that many others had their websites ruined by other auto updates

greetings and many thanks for any help you might offer