Hey all - problem is in the title. Looking on line told me to just force restart (home and power buttons), plug back into iTunes and choose update. I did that and it told I would have to restore the device to 11 even though I didn't get there in the first place.
So... now what? Thanks...
I went to somewhere (23rd of December, Brussels time) and hadn't got my Lightning cable with me. At 5 PM my battery was around 20%. Because I hadn't got my cable with me I powered off my iDevice to save the battery that still was available. After an hour I needed something that I wrote earlier...