iPhone stuck on "slide to upgrade" screen after updating to iOS 9. can't backup or restore

I updated my 4s to iOS 9 today. After the update finished, my phone restarted and asked me to connect to wifi. then it went to a white screen that says "slide to upgrade" but it is unresponsive. I tried backing up my phone so I could restore it, but iTunes just says "Backing up Iphone" but it doesn't seem to be working. I let it sit for hours but nothing happened. I then tried to restore it and it says i can't because "find my iphone" needs to be turned off. I can't access my settings on my phone because it is stuck on that screen. Don't know what else i can do