Fridge has frozen some of the contents

Can anyone help with a problem I am having? I am home on my own and have no-one else to ask 😅

I have just got some milk from the fridge and it has partly frozen. I also have some yogurts and a piece of salmon in there which have also frozen.

I haven't made any adjustment to it at all (there is a dial that goes from 1-5 and it' always been set at 3)
Is it broken? Why would this suddenly happen?