A few weeks ago, I had just pulled out of my driveway and realized that I hadn't reset my trip odometer and Energy Efficiency screens yet, so I did so while driving. Because I had my eyes on the road, I couldn't see what buttons I was pressing. I apparently pressed something that affected the brightness of the Dashboard, because it made everything go completely dark, and it really felt like the car had died on me. If my memory serves me correctly, I couldn't even see my speed, battery bars, anything. I pulled over, turned on my hazards, restarted the car, but it was still "dead". I tried to reproduce whatever it was that I pressed and I eventually got the lights back on.
I doubt that this is what happened to you, but just thought I'd throw it out there. Hope everything turns out alright with your Leaf!
Former Ride: 2012 Leaf SL, Ocean Blue, Leased 1/27/2012, Returned 4/27/2015, 37.7k miles & 12/12 bars
Final LeafSpy readings: AHr 60.73, SOH 92%, Hx 90.90%, 250 Gids on full charge
Current Ride: 2012 Nissan Rogue SL AWD, Black