Yes, and it’s absolutely terrifying. I know at that point I wouldn’t feel anything but it’s depressing to know that everything you have, and will ever know, could be destroyed in an instant.
Do not despair, in all likelihood you're just a Boltzmann brain anyway.
But I can remember last Thursday!
But that is life - you will die at the end. This is not a reason to be depressive, there is a way to find freedom accepting the volatile nature of everything. Enjoy your life, do not harm anybody and do positive work.
Not sure of the math but definitely not an instant, at that scale.
At 10% the speed of light, an object would traverse the distance of the diameter of the Earth in ~ 0.04 seconds. Which almost certainly would be too quick to be perceived by anyone.