Same just happened here. I woke this morning to find the Bangle2 on a white screen with a default Anton clock. When I connected to the apps page, it reported that the firmware was 2v11 when I have been running 2v16 since it came out. None of my loaded apps were present.
I have just spent an hour, reinstalling everything from the firmware up. It seemed like the Bangle2 had gone back to its original status including the Welcome app which I have never had installed since I first wiped it when I received it.
I really hope this isn't the beginning of the end of the Bangle2- my last Pebble is just on the way out (I only use it as a wake up timer by my bed these days as its battery charge won't keep up for more than a few hours at this point).