Of course, first of all I'd advice you to talk to your parents again. But since I know nothing of the situation, I don't know whether that's possible.
So I'll instead move right on to:
Do you have a therapist you can turn to? psychologist, psychiatrist? Have you looked into the telephone book or on the Internet and typed in your town and youth services/youth welfare office? Have asked your parents for how to contact your GP? And if you really have no idea who to call, go or call the police. Really.
In any case, try calling. Don't give up even after your third to fifth attempt... Write down everything. Something like 'Hello, my name is... I have autism/AS which is a form of autism. It's hard to speak. I've been thrown out-' and so on. People will be more relaxed if you sound crazy on the phone or in person if you state you have autism. Say word for word, forget about the sentence.
It doesn't matter if you stutter or make long pauses between words and are hysteric and partly mute. Seriously, it doesn't matter. The other person will understand you anyway.
If that totally doesn't work, write everything down (and if you find you really can't talk at all now, also write down your request for them to call your GP or someone else) and go see a neighbour. Yeah, they may look at you oddly, but who cares.
If you go to a school, then go to that school on Monday morning with the same request. Right to the secretary or principals office. They must help you.
If you got a job, go see your boss with the same request.
Have it all written down so you can pass them the paper in case your speech leaves you right there.
No giving up before you tried hard, you know.
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Autism + ADHD
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The trouble with having an open mind, of course, is that people will insist on coming along and trying to put things in it. Terry Pratchett