I'm not a doctor, but I don't think you'll have much luck finding one to help you with that. The legality behind physician-assisted suicide will definitely vary by country, but I'm pretty sure no doctor will go through with it over a mental health concern. Maybe if you had like a traumatic brain injury that made you unable to care for yourself, but that's technically a physical health issue
I don’t want to die but I don’t think there’s any other choice
This statement is reason enough to prevent a doctor from killing you. If you don't want to die, they won't make it happen - consent is super important for something that grave. Suicidality is also very often a temporary thing, some day you might change your mind. There's a reason that euthanasia is used almost exclusively for the terminally ill.
I'm sorry you're struggling. The specter of homelessness hangs over my head too, and I often think I'd rather be dead than have to deal with that. But every time I've almost died I really didn't want it to happen.
You probably should still talk to a doctor about this. If you'd rather kill yourself than live without support then that should help illustrate the severity of your disability. Not knowing what country you're currently in, I can't tell you what support is available to you - but there's almost certainly something that can be done to help you.