Help! 6D lcd has stopped working and autofocus no longer working!

Question

Ok - I scoured the internet as best a I could and could not find any troubleshooting with the issue I am currently having with my 6D. The camera stopped working in the middle of photos I was taking of a sunset over the lake. The camera LCD was no longer working (allowing me to look at photos, bring up the menu etc) it was just black. However, when I turn the camera off, it displays the "sensor cleaning" on the back of the LCD so that must mean the screen is working, its just not allowing me to see any information displayed by my camera.
The display at the top right of the camera by the shutter button that shows all the aperture, ISO and shutter information works and is accurately monitoring the light change. The display when I look through the viewfinder showing the light meter is working too. I can change settings in manual mode and it will display the changes in both the viewfinder and upper shoulder display.
However, the other issue is the autofocus isn't working correctly. When the lens (and I've tried different lenses, they all have the same issue) tries to autofocus, It sometimes will correctly (I can see it hit focus when the small box in the viewfinder lights up ready) but the majority of the time It will just act like its in manual focus mode and shoot everytime the shutter is pressed.
THE OTHER thing is the shutter button is permanently pressed in. Its not "raised" like it usually is allowing you to lightly tap it gain focus. I cannot change where the focus point is either, its permanently stuck on one to the right of the center point.
One small detail, at some point during my shooting today the rubber eye cap around the viewfinder fell off. Not sure when this happened because I was wearing glasses and didn't notice it came off but was wondering that would cause any of these issues (can't see how it would..)
I shot A LOT of photos today, all in RAW. I mean.. I was literally shooting all day for 8 hours, NON-STOP so I'm not sure if was something that could cause these issues either.
The camera is still recording the correct image data to the card since the issue started, I checked on my computer.
Not sure whats going on here, and I'm really worried! I'm worried that water or sand could have gotten into the camera and cause the issue, even thought I was being extra careful that this wouldn't happen since I was on the beach (Lake Michigan, fresh water).
If anyone has any ideas to help please let me know!

Answer 1

I suspect your last paragraph explains the problem. Try unstick in the shutter button by trying to carefully insert a business card between the button and camera body and sweep the circumference of the button to remove the sand particle.
John Hoffman
Conway, NH
1D Mark IV, Rebel T5i, Pixma PRO-100, MX472