Please post your zone and which hemisphere you're in -- it will help immensely to know whether you are in spring or fall mode, and how much longer you have before frost, if any.

Oh, I live in Israel (northern hemisphere), I have no frost in my area.

Just checked this afternoon on my squash and things are getting worse! I think mosaic virus is attacking my poor plant!!

Not mosaic. Not any disease. Instead, short of water.

Very nice image of an acute water shortage. Did you have a sudden hot spell?

Is it growing in the pot in the first image? If so, need a larger one. Much larger.

Well actually, since one of my raised beds was damaged couple of weeks ago, I had to move everything to pots. Since that incident my squash had a lot of troubles. And I do water but maybe you're right, I'm not watering it enough. Will it be OK if I'll water it correctly?

maybe it didn't like the transplanting. It's pretty big for having to go through a move. Certainly try watering and see if it bounces back.

The new growth on it may be fine with adequate water but you will probably lose many of those older damaged leaves. I would trim off the very worst of them now to reduce the stress on the plant.

You don't mention the size of the pot. As mentioned, if it survives the transplanting then it will need a very large pot - 5-10 gallons which I think is approx. 15-30 liters - to survive.

Dave

Another opinion --

I would keep all leaves with any little bit of green on them as the plant needs all the help it can get at this time. Those brown parts are dead, not diseased. So the damage won't spread/increase unless the plant remains short of water.

Likely moving the plant left many roots behind. It needs a bit of TLC, and perhaps light shade, to get through this crisis.

I would also check the backside of the leaves for possible mites or similar.

Thanks to everybody!
I finally fixed the raised bed, and I'm going to transplant it back tomorrow (going to do it with extra care)

Here is your problem. You can not transplant squash. It has a tap root.