Hello &Help please

Hello everyone, I am new to this site and not sure wether this is the best place to post my question.. but il give it a shot, I am in need of advise, My eldest son is 7 and I have been struggling for the past 2 years to get help for him. He has always had a few funny quirks shall we say but is has hightened over time, I have asked for help from the school, doctors, social services and any one I could really. I do not know if he would be considered as having Autism but I do suspect he is on the spectrum. I have voiced my concerns and just been told hes a bright child that's being naughty for my attention! This is so not the case, he has huge melt downs, he tends to go for hitting out if they are not handled correctly, then he will completely close off as if you are not there, and he will cry for hours until you can find away to get him out of it ( well i get him out of it as i'm the only person who can) He struggles in a big way with change, even the slighest change is to much to handle, I have to tell him exactly what we are doing, where we are going and who will be there, if this doesn't go the way it was planned he has a melt down, He also suffers anxienty and some days just doesn't want to leave the house, he has no awarness of any type of danger and has no respect for aurthority, myself, my parents or the police, i'm at a loss what to do next to help him.. he's such a beautitful bright boy, it's breaking my heart to see him like this, he's struggling alot at school and I fear if I don't get some sort of diagnois and help then school will get worse and he will slowly drown with all the pressures of every day life flooding in on him.. Can anbody relate? Is there something in thinking he is on the spectrum or am I just being silly like the school says? any advice would be greatfully recieved xx