There's no denying that there's tremendous suffering that comes with wd, and insomnia can be especially brutal. [...] is absolutely correct from a neuroscience perspective. Focusing on the negative, and programing our brain computers with statements like, "I'll never heal. I'll never sleep again. I can't survive this." reinforced the neural pathways that activate our sympathetic nervous system, release stress hormones, and make sleep more difficult. It's like a habit. The more you reach for that cigarette when you have a cup of coffee, the more you crave a cigarette whenever you even smell coffee. Indulging and entertaining catastrophic self-defeating thoughts strengthens those connections so just having [...] fall or seeing our bed, activates our sympathetic (think fight-flight) nervous system.
Of course those thoughts are going to come. Notice them, label them ("Oh, there's my catastrophic thinking again. My brain is doing the best it can and is healing. Back to the present moment now."), let them fly around, but don't make a comfy, cozy nest for them. Forming new pathways, new habits, is hard work but very much worth it.