I've actually posted about this exact thing before! I would feel so much less guilt were it not for the fact that my sibling CTB'd years ago. I feel a lot of obligation towards my family who've already grieved one child, and I feel jealous that I got beat to the punch.
And it's made so much worse by the fact that my Dad knows I've had suicidal thoughts in the past and is terrified that I'll be the next one to die. He does absolutely everything in his power to try and make me happy. One time, I slept with my door locked because I didn't want anyone coming into my room, and he was banging and wailing at the door acting as though he knew I'd killed myself (I hadn't even attempted to). I'm sure he's exhausted too, but always being suspected as a potential corpse in the near future any time I am left alone... it's exhausting, and it wears me down, and I just wanna be how I normally am, without my dad constantly trying to get me to do shit I don't wanna do.
I'm trying to shed this 'guilt to stay alive', because I know that all it's doing is prolonging my suffering to save others grief. I want to muster the willpower to make my fleeting existence any less of a burden on the ones who love me, and when I'm gone I will finally be at peace. Peace is all I've ever wanted.