I understand. My mom will be beyond devastated when I go as well and I'd say that it's been the biggest psychological barrier for me over the years. She's told me in the past that if I plan to die, I should tell her, so that she can go, too, because she won't be able to handle the grief. That puts me in a really tight position, though, because I cannot tell her without her crying (which is understandable; it's undoubtedly an extremely emotional thing) and trying to stop me, and having to constantly deal with the emotional part of all of it while I still have to take care of the logistics before I go. I know that it sounds selfish and maybe even cold (which is not how it's meant at all), but I'm just way too sick to deal with that on top of the profound and unbearable strain of simply making it through the day, in addition to having to prepare for my exit in order to make the aftermath as "smooth" as possible for the people who are left behind.
My life is like one big game of chess, and I need to be strategic in how I approach every last little thing so as to reduce the overall amount of suffering as much as possible. Every last bit of strain – be it physical, psychological or emotional – makes me significantly worse, and I need to avoid situations that will make me worse whenever possible. I cannot afford for my condition to get so bad to the point where self-deliverance is no longer possible, and I've been pushing it for way too long.
I would love to be able to warn my family so that they can emotionally prepare themselves as much as possible, but that's just not the world that we live in right now. Suicide is widely seen as nothing but an irrational and impulsive act that must be stopped at all costs, regardless of how much pain the sufferer is in or how low (or non-existent) their quality of life is, and even at the cost of completely disregarding the sufferer's wishes and making their life even more unbearable just to keep them alive for the sake of keeping them alive and so that other people don't feel sad, and I think that's super twisted. Of course I don't want my mom to hurt, especially because of me, but the shitty reality is that I'm suffering relentlessly and the only respite lies in death. No matter what I do (or don't do), someone's going to hurt, and I hate that so much. I can only hope that my mom will understand why I did what I did in the way that I did it, and that even though it might not feel like it, I really did take absolutely everything into account.
Sorry for the blabber. I guess what I mean to say with all of this is, I completely understand where you're coming from with this, and I'm so sorry that you're in this position. It's a very difficult situation, no doubt about it.