Oh hi I’m a psychiatric nurse!

Most important: Pick the three people you trust most in the world, put them in order of who you want making decisions for you the most, then talk to your doctor about what paperwork you need to sign for that. Then talk to those people at length about how you want to die and what would make you feel the safest and happiest day-to-day. Think about what things you do for fun / relaxation, what kind of music you like you listen to, etc.

If you’re up to it, I also highly recommend Wellness Recovery Action Planning. It’s more designed for people who are more likely to recover, but it’ll give you a template to go off to communicate your day to day needs in a written format for your legal decision makers and healthcare professionals to make you feel safe and comfortable as you progress through these next few stages. And if you do this have a special section just for music; it’s the part of your brain that’s likely to keep working the longest. Make two playlists, one to dance / have fun to, and one to relax / sleep to.

I wouldn’t fuss too much on the gun thing unless you already have one / have been used to having one for most of your life. If you were never a gun person before you’re unlikely to randomly just go out and buy one.

Good luck and I really hope you’re able to find trustworthy people to make decisions for you because without them to actually carry out your wishes, literally anything else you decide on now is completely moot.