Your world just shattered like a glass floor beneath the weight of the world that you dropped because you could not carry it alone. The only way you could have carried it this far is if someone shared the load with you. You could not have forced them to help you because they had the weight of their own world to carry. The kindness of their heart is the only thing that could have possibly persuaded them to do this with you. Surely, if they were kind enough to do that for you, you would try to do the same for them. Somewhere along the way, however, you became separated. Maybe you know how. Maybe you know why. That part doesn't really matter. At the end of the day, how or why don't matter. How and why are questions of mechanics and motive. How and why don't change anything. At the end of the day, something else keeps you awake at night. It isn't your understanding of what happened, nor is it your understanding of the purpose behind the event, nor is it your understanding of what triggered the event, be it separation, be it collision, be it good, be it harm. It isn't the cirumstances surrounding the event that plunge their claw into the tissue of your mind and soul.
Rationality. That is weapon of the beast that haunts us. Is rationality bad? No, but it can only go so far, and this is where it begins.