So blue tooth was working just fine with my wireless keyboard and now not so much. I see the Bluetooth icon on top and its not allowing me to see anything about the setup like it did before. now it's just telling me that it's "Not Available"....... looked for Bluetooth options on preference window and all it found me was the sharing folder where there was nothing about bluetooth.
Shut your Mac down - not reboot, do a shut down - then boot it up and see whether the problem has cleared. As it happens, I had exactly the same thing a couple of days ago: a reboot didn't cure it but a shut down did.