Feeling my way in the dark. Advice please

Hi, 

Im having problems with my sons pedeatritions ( sorry spelling is rubbish) the first one has vanished after telling me he's not autistic after a3second glance she has requested blood, urine and MRI tests which have not appeared even after phoning. Then his appomeant date, location and doc was changed..he is 27 months old ariganly under thier care beacause of having a big head, but he doesn't  say a single word and only started walking a month ago, he ignores  everyone most the time except peak a boo games. He doesn't point or follow any instruction,  closes every thing all the time hates sand. Ect..

He is the happiest little man ever. is treasured by his Dad and brothers we'er all looking to find a way to reach him in his little world, and help him achieve his potential but we need a diagnosis. he matchs the signs of autisum from what I've read. I know he's not the same as my other children were at that age. 

Any advice on how to the ball rolling I'm tired of being told he ok, but we'll see him again in 3 months. And not knowing were we stand.

thanks