Hoping to move back to the UK after several years living abroad

Whenever someone asks me if I would like to move back to Britain I always tell them yes, only when the right time comes. So that I will be settled down in a special needs accommodation and feel safe there. Every single I think about where I feel I should be today, feel I should be back in Britain where I belong. Even though Britain is not the same as when I was taken out of it I have to keep reminding myself that life in America hasn't exactly been pleasant for me, with the many negative experiences I've had and the negative events that have taken place. For several years since being in America I have been trapped inside the same unpleasant and vicious cycle, which I still find myself trapped in today and still find myself begging God to show me the way out. I still haven't forgotten how I ended up going crazy at one point, constantly hitting my head against the wall, ripping some of my clothes to shreds - something I never used to do whilst still in Britain - and venting my frustration on those books I got from that Fenland special needs charity bookstore, because all I have ever done is find myself being moved from one rented house to another and subjected to endless constant mental and psychological abuse whilst being restricted to being trapped in this unsuitable and toxic household without any way of escape, wishing I could escape from this unpleasant environment and take refuge at some shelter far away somewhere. The whole time I've been in America I haven't been able to get any of the professional help that I need. All those autism treatment clinics and special needs cognitive behavioural therapy programs I've been looking into and fighting to gain access to, I've been cruelly denied access to them since coming here because of being denied green card residency which I need in order to be given the right therapy and treatment. This has gone on for far too long, and also my severe depression seems to have worsened since being brought over to the US to the point where I have become an extremely aggressive, hateful and bitter person. I didn't ask to be put in this struggling situation because I didn't even want to move to America in the first place - my parents decided to bring me here. Even though my parents only wanted the best for me they also need to consider my mental health and wellbeing; they need to consider how I haven't been coping at all as of late because of my needs having gone ignored and not being met in any way. If I had been allowed to stay in Britain as I would have wanted then I would have been able to make use of the National Autistic Society and their special needs services and programs; I also would have had the chance to focus on getting professional help from the NHS. Especially because America is very cruel and not a safe or ideal place for those who are extremely vulnerable and suffering from mental health problems. So by having the people in my life discourage me by only pointing out the negative aspects of Britain it only makes me feel even more miserable and depressed.  As a British citizen I should be allowed to leave America and move back Britain whenever I choose to; I should be given a choice and not be placed where I don't want to be. If things are not working out for me over here then it is not fair on me to be forcibly kept here against my will if I am not benefitting from these limiting restrictions or anything else at all. I need to be in the right type of autism-friendly environment where I will feel properly settled, where my sensory issues and other autistic traits will not be triggered in any way because nobody will see me as getting fixated on autism spectrum disorders.  I see other non-US citizens freely moving back to their own home countries, so why shouldn't I be free to move back to my home country? Why should anybody stop me from returning to the UK which has more options for those with disabilities and special needs?