My wireless network suddenly disappeared and all devices that were on it were disconnected. However, I eventually realized that one of the connections with a name I did not recognize was mine, as the same password worked. Can someone explain how the SSID can change without my knowing? Should I change the SSID to a new one?
If you log in to router, do you see any devices connected via wireless on new ssid?
I would change ssid and password.
also change router password
Was it changed to something generic?
If not, its possible someone hacked your router.
That's why I suggested you also change login password to router.