You could connect the pi itself to a keyboard and monitor and then login through the command line. You could then use nmcli to see what’s going on (look up nmcli, home assistant, ip and you’ll probably find a good guide).
You could also check on your router’s admin panel and see if maybe its ip address has just changed.
In the future you should download your snapshots to another location. I do this before any update, and before I really muck with things. If you’re okay with Google drive there’s a nice add on that automates this process.