I am in the same situation. It's only because of others that I am still alive, but sometimes it doesn't seem like a good enough of a reason to continue living, unless you can find some way to make it beneficial for yourself as well. If these family members that you are concerned about are beneficial to have in your life and you like being with them, then maybe it won't be a bad idea to stick around for a while, as long as you spend as much time with them as possible. If they are toxic to be around, then I would say screw them. Family members that only want you around to benefit themselves are certainly not a good reason to stay in this world when you are ready to leave, so there is no sense in making yourself miserable for their happiness.
It really does make the decision to CTB much more difficult when you are worried about how it might affect your family, but taking care of yourself is the most important thing. Since you are having a hard time figuring out what to do, then it's likely that some of your family members are good people and you don't want to hurt them, which is understandable, but if you stay alive for them and continue to feel worse, then it's not worth it. I recommend leaving them a note to explain why you left (if that is what you end up doing) because it might soften the blow.