You're setting yourself up for either dying or surviving in a terrible state where your organs will be severely damaged and you're no longer independent. I'm not in the medical field so I can't tell you how your body and mind will be like if you survive SN, what I can tell you is that you'll put yourself in a much worse position than you are now.
If you want to survive, which from your post you do, then please don't attempt with SN. Maybe call a suicide hotline or emergency services if you feel like their services may help you. Tell them you're a danger to yourself and you will attempt if you don't receive help.
Like others have said, that experience may be worse for you, there's no telling as it entirely depends on the quality of the services where you live and how receptive you are to their treatment plan. I've never been inpatient in a psych hospital, I was outpatient, and it wasn't great - got shouted at, psychiatrist interrupting me, threats that if I didn't return to work I'd be fired.
I'd recommend checking out the services you have where you live, reviews, maybe try to find other users on SaSu that used them and wrote posts about it. I wish it always worked well and people felt better after using said services but unfortunately that is not the case.
Please take care, a cry for help may give you help but it may not be as helpful as you'd imagine...or it may harm you further...