IPhone 5 - Unable to join the [wifi] network?

Please help!
I'm very reliant on my iPhone for internet access throughout the day and for some reason, out of the blue, my home wifi is refusing to connect with my iPhone 5. The wifi worked at school earlier today without any problems but when I got home and tried to connect to our wifi here the message "Unable to join the network" continues to pop up.
I've tried the airplane mode trick (turn on to airplane mode, turn phone off, turn phone back on, and then turn off airplane mode), resetting the network settings, turning my wifi router off and back on, and the obvious clicking the wifi connection on and off from my iPhone.
I'm tempted to call AT&T or Apple Support but from what I've read online they haven't helped others with this same problem. Our home wifi works just fine on my laptop and our main desktop computer.

What can I do to get the wifi back on my iPhone? Please help!

Try this go to the page where it list available wifi's choose other then fill out your wifi setting.