Sorry if this is a dup post. My pc glitched.
In the psych world "having a plan" means you've researched ways of killing yourself and decided on one particular method. You have the materials you need and have the place picked out. You've got the details planned and you've written a note or at least know what you want to say when you do write on. It means you've made a conscious decision on this course of action and you're just waiting for the right time.
So if you're just remembering an old plan, that's one thing. If you're committed to this course of action and it's only a matter of choosing the time to implement, that's having a plan
That said, I hope you're just remembering and that you don't actually have a plan Humpty Dumpty