Sorry to hear about your dog's sudden restlessness.
To me, it sounds like anxiety or something close to a panic attack. My Gracie dog (heeler mix) does the furious "digging" at times on our carpet in our bedroom, but usually only around thunderstorm times. Or she will come paw us relentlessly. It is hard to watch because I know she is ultra stressed if she is doing this self protection type of primal digging.
Sometimes this type of anxiety is caused by a single event, and now the dog is worried that it may happen again at that same time.
Do you recall any event that may have occurred around that time? Did it thunder? Ambulance siren? Fireworks? Argument in your house? Phone ring suddenly? Very windy? Did your dog hear a wild animal (opossum,raccoon etc) in your yard? Did you get up to go to the restroom in the middle of the night and stub your toe and scream? Roll over onto your dog in bed and startle your dog? Something fall in your house? You get the drift.
Maybe your doggie just had a bad dream and woke up suddenly? You may never be sure at this point.
What to do now? For me, when Gracie starts doing this, I do one of several things, or a combo if needed, to get her to settle and relax or go back to sleep.
1) Give her a massage if she will let me (different then petting)
2) Give her ultra yummy food-- wet food or meat or cheese
3) Put down my robe that smells like me for her to sleep on (comforting)
4) Open up a small"cave like" space in our bedroom corner for her to sleep and feel more secure and protected
5) Run her tricks with her (if she is able to focus) and pay her generously with praise and food
6) Turn on relaxing music to soothe her
7) Tell her we are all good, no need to worry
You guys have no idea how many times in the past three years I have gotten up dead tired in the wee hours of the night to comfort AND counter condition
Gracie when she was spooked. But it has really paid off for sure-- her fears are nothing compared to before and she can now think
and not just react
in most all situations!!
Hope this helps and you all get some sleep soon!