Maybe I'm a nutcase, but I've taken the time to prepare a set of scenarios under which I would no longer want to live, and think about what would need to be taken care of to exit the world without undue burden on those that depend on me. That seems like an eminently rational thing to do.
I believe professionals would categorize what you wrote there as "planning suicide". So long as you have not started "taking care of" those things you have not begun executing your plan. Planning is a rather big step beyond contemplating - I hope you're doing better now. You may also want to consider that actually getting your affairs in order could be an enabler.
It's evaluating a set of contingencies. Like, the general staffs of armies make war plans that they will never execute, unless the particular parameters fall in place, all the time. To do otherwise would be irresponsible.
The public health responses to you should be very different to the people who experience rapid onset despair.