The fallout would be immense, especially with my immediate family (sister, mother, and father), they would be looking for reasons, grieving horribly and always questioning what they could have done differently. My mother would be hit one of the worst (she is nearing retirement age, but not fully there yet) and would be grieving for a long time. As for my father, he would be sad, but eventually he would move on and do his best to live the rest of his remaining years life (he's also approaching/at retirement age). It is one thing for someone in the family to pass, but going before one's parents would cause a lot of grief among one's parents. However, on the same token, I never consented to birth, therefore, I don't believe that I should just 'live' for their sake (or anyone's for the matter).
As for my sister, she would indeed be very sad, but she has a husband and they have their entire lives ahead. The worst part would be that my sister (she's basically a psychiatrist in training - doing residency in other words) would likely push the angle of suicide prevention hard and write off suicide as an 'irrational choice, mental illness' without even considering all the circumstances. It sucks that there are people like my sister out there (in fact, the majority of the general population in the world) and there is little, if anything to change their views, but I can't just continue to live and suffer tremendously just so people like her (and there are a lot) don't try to use my death as some sort poster boy/girl of suicide prevention.
Then as far as other people in my life, they don't really have contact on a regular basis, but upon hearing the news, yes they would be very sad, but just like my immediate family, they would be a bit less sad (because it's not their own family), and move on a bit more quickly. The unfortunate part is that a fair amount of those people are religious (no offense to religious people in general), so they would view suicide as a 'sin' and that is simply not true (as someone who is an atheist who studied the Bible and understood it more than most Christians), and even if it is, it certainly isn't a sin enough to go to eternal torment, aka Hell. Now in regards to secular people in my life, they would write it off as 'mental illness' and 'irrational' choice, which is really a spit in the face.
Regardless of the fallout or impact, I cannot simply just stay alive just so people don't feel sadness at my passing, and also, once I'm dead, nothing matters beyond that point (as I wouldn't be around to argue, challenge, or even suffer the aftermath). When the day I die, it would be a relief from suffering and my notes would serve as a purpose for understanding and closure. Then beyond that, it is up to the living to decide how they wish to proceed from that point on.