Yosemite killed my wifi

Upgraded to Yosemite this evening on my mid 2011 Mac mini and now I don't have wifi. The wifi menubar icon has an "x" on it and when I click on it, it says, "Wi-Fi: not configured." The only option is to Open Network Preferences.

When I open Network Prefs, there's no wifi option on the left, only ethernet, Thunderbolt, firewire and bluetooth. I try to add a wifi network via the "+" sign, but nothing gets added. My wifi network is working fine as my wife and kids' computers (on Mavericks) as well as all of our iOS devices connect to it fine as usual.

Luckily, my Mac mini is normally connected to the internet via ethernet cable, but I need to figure this wifi issue out.

When I go through whatever diagnostics, it sees my wifi network and allows me to enter my password, but then it won't connect. But, it only shows my wifi network via these diagnostics - not from the wifi dropdown on the menubar and not in Network Prefs.

Any thoughts?

Thanks.