Mine did the same thing last night and also had other graphical sluggishness and choppiness but MSFT posted a Windows Update at around 11pm EST that fixed those issues along with the screen not turning off and running warm...at least on my Surface 3. There were also several firmware updates posted yesterday for the Surface 3 family. Make sure you check for updates as soon as you can. Good luck!
Thinking of reverting to 8.1 too. Still have the problem and about a dozen people on Microsoft's forums have reported it too. There are more than a few people having problems with brand new Surface 3 LTE's also. Can't believe how poorly Windows 10 is upgrading on their own machines.
I hard reset mine (shut down, then hold the vol. up and power button at the same time) and set my power button the "Hibernate" when unplugged. It seems to not die overnight now.