Tumblr Broke my Tablet?

I was using the Tumblr app this morning when the screen suddenly froze. The bar at the top disappeared, and I can't touch the screen anymore. The home button doesn't work, I'm stuck on the same screen showing the top of my dashboard. I held down the power button and the little menu saying "Shut down, Airplane Mode, Restart" comes up but I can't choose one to restart the tablet. The volume buttons work perfectly fine though. I don't know how to fix this. It's been stuck like this for a while. Please help me.

(My only idea now is to wait for the battery to drain, but it was last on 100%)