There was a Sonos update yesterday, so it’s perhaps a case of your system is scheduled to update automatically overnight. I would wait a while to see what happens, but it sounds like you ‘may’ have lost your internet connection during the update, by coincidence. I guess these things can happen - if it lasts for a very long time, then I would simply reboot your router, but things may sort themselves out eventually.
What might assist you for future updates is to reserve all your Sonos IP addresses in the routers DHCP reservation table, making them static on your network subnet.
Hope you can manage to sort things with a router reboot after an hour or so, if not, then give Sonos support a call via this link:
https://support.sonos.com/s/contact
Thanks for the response. You were right. I just needed to be patient. All sorted now. Ty!