That's a known deep sleep problem. The fix is to force a hard reboot. Press your brake pedal and both scroll wheels and hold them until the MCU screen shows the Tesla "T", then release all as the reboot continues. Note you may have to hold the brake/buttons for what seems like forever. I've never timed it but it has gone as long as a minute. Once the T appears, the reboot may take another minute or two until everything is powered up and you can drive, but even then it may take another two minutes afterwards before the bluetooth connects back up to your phone or the GPS position data boots up.
It can be scary to find your car in what appears to be a dead state. While I don't know exactly what happens, I think of it as the car (like a PC) going into a sleep mode and nothing you do (moving mouse, pushing keyboard keys, mouse clicks, etc.) will wake the computer up. Only choice is to hold the power button until the computer powers down, then release it and push the power button again to restart the computer.
I have ONLY seen this state a couple of times (less than 10 in 2 years) and it has always been a case where I walked out to the car and wanted to start driving...sometimes after it sits in a parking lot for 5-10 days, other times I was away from the car for an hour or two and returned...no commonality on what put it in this state. The good news is that the hard reboot described above has always worked and I was on my way...
Hope this helps.
