On Consciousness

A few years ago I developed insomnia. The cause was a sudden and heavy onset of somniphobia, relating to the gap in concsiousness. To me, who you are is almost entirely comprised of the state of your mind, all thoughts and memories you have at any present moment; a complete mental reset and gap in your line of consciousness was terrifying, it feels tantamount to dying. The Boltzmann brain thought experiment describes a brain that spontaneously forms in void, complete with all memories of a life before its creation. How can I prove this isn't the case? I can't. To even convince myself of my own consciousness there has to be a running thread, the ability to (at least somewhat) track where I was mentally and where I am now. Sleeping cuts this thread. It's hard to describe the immense existential dread from this "irrational" fear, because to me it isn't irrational.