They aren't going to kick you out just for calling for help for yourself (I hope). That would be very strange. Did they threaten to kick you out the time they saw your cuts? I don't think they would. Tell them you're suicidal, since you are. Pack some underwear, jeans, nightgown (nothing with drawstrings), slippers, they usually provide toothpaste and toothbrush and soap and shampoo and towels at the hospital. They won't let you bring in anything sharp like pens and pencils. They'll provide those too. You can bring a book or magazine. ChapStick or anything like that. Lotion they may or may not let you keep (they'll hold stuff for you if they don't allow it). It will be strange but it's only for a week or less, unless you are extremely unstable. At least you'll have done something to try to change the current situation you're in of needing help and not getting it. The hard part will be returning home because your parents won't have changed. You need motivation to change your circumstances and the course of your life. It's not certain that starting a treatment plan will work, but it's possible.