Hi. It is a horrible plan. Either your family will notice and interfere, which with its consequences about how they react to it, or you yourself will. Like the previous comments say, most likely, almost a guarantee, the hunger will take over, override the brain and all your other pains and force you to eat. I've stayed for similar and longer durations of time without eating, not as a means to die cos I know that doesn't work, you always end up changing your mind and feeling like eating is kind of the best idea ever.
However I get where it's coming from. The "not doing something rather than an active choice", yeah. If you are used to that overwhelming tiring depression and innaction and just lying there wanting to die all day this is one of the first things that comes to mind and you Want to do it. It feels like the next logical step of lethargy, just one that really doesn't go anywhere due to the way our brains are wired... But I feel you there.
Don't know if you've eaten or drunk already, you probably will soon. Specially drinking I'd say pretty important once you start feeling like total shit. Up to you when, really this whole thing matters little, and I don't mean it in a bad way. I'd like to think no pain you go through will be in vain, nor anyone's, in whatever form that sentence may take, but this pain you are inflicting on yourself right now born out of all your other pain... sadly won't lead anywhere. It'll go in a matter of time. And I'm really sorry you are even in a position to have wanted to do this. I hope it did a bit of a reset and you can feel a bit better afterwards even if just for a little, that can sometimes happen so... here's hoping anything good can come out of this. Big hugs <3