i closed the game last night and today when i opened an event appeared saying that there was a fog and some food was stolen
but everything is gone! all the trees are gone , all the food ( i have 0 food) and the alchemy lab is in ruins so i can prepare no potions
what should i do ??? and what tech should i buy now to help me through this disaster ??? ( i have 126,000 points ) !!!

What levels of tech do you have now? Have you planted the entire orchard?

As far as the alchemy lab goes, you can fix that without buying any tech. You just need an adept or higher scientist. Pick them up and drop them on the various bottle/dishes scattered around the village. When that is fixed, you can experiment with potions or try some that others have posted here.
Good luck.

i have level 2 of every tech , and of magic . (but i have no nature), but everything is in ruins now , i have to rebuild the bath and the huts ( working on them now),and i had to rebuild the LIFT , so i did it and planted 1 tree. i managed how to get rid of the sharks so now they are safe regarding the food,i think!
BUT they can make no more babies because all huts are broken again!
i'm still wondering what tech to buy now ??? should i buy the restoration and start building the 3rd hut , or there is something else that they need now more than the 3rd hut ???

I've seen this bug reported a handful of times in the forum. It must be fairly rare since there don't seem to be many reports.

How many villagers do you have? Are you close to the population limit that will mean you'll need to build a third hut? Unless they are close to that limit I'd concentrate on getting the first two huts rebuilt now, and then the other puzzles you've already completed once. Now that you've got unlimited food back there's nothing that the villagers need, although Medicine might be useful to prolong your villagers' lives.

That bug is very rare, but we do have an answer in our Support FAQ about it.

Thank u both , ok i'll try sloving the puzzles again and then build the 3rd hut , i have a population of 27 villagers , can they make more babies after rebuilidng the first 2 huts?
@LadyCF: i understood from the link you gave me how to make copies of my safegame files and put them in another folder in case this happened again , but i didnt understand , if this happened again and i need to use the copies i made , what should i do then !! recopy them to "My Dociments" (where i found them first) ??

Yes, you just copy the backup files into the original savegame folder and they will replace the 'bad' ones.