You WIll go to a state mental facility, for a minimum of 72 hours. Maybe a week, depends. Cops Hate dealing with suicides, or rather, attempted. No matter how remorseful you act when they get there, or how apologetic.They often get rough. The oldest trick in the book is:"May I talk to you?", you don't use a police chain, they crack door open, they pull you outside and cuff you.
This detaining IS an arrest; just because you dont go to jail doesnt mean it isnt. Might even have a record of it, later.