ADD - ADHD ?? - Advice & experience needed please

[XandaPanda]

This may come across a bit jumbled so please bare with me .
My son is 4 in just over 2 weeks and he has always been different but i have just put his behaviour and personality down to 'terrible twos' until the other day when somebody mentioned it to me .
I have looked and he does seem to have a few of the traits quite severely, He has absolutely no sense of danger what so ever (runs in to roads,runs away,will jump off anything no matter the height or distance, i even have to keep all the doors and windows locked as he escapes and plenty of more dangerous things) i really did put this down to him being a boy but now im not so sure as i cant take him anywhere without his reigns or him been in his pram.
He is Asthmatic (since he was born) and his Pediatrician and other Doctors have always said they have never known an Asthmatic child have so much energy and even when he is struggling to breathe he still keeps going (bit like a duracell bunny) , Always picks fights with the biggest kid in the playground .
I haven't mentioned this to his School (goes to a Prep school) yet but i did ask and they say he is very well behaved and well mannered yet at home he is like a mini tornado he just does not stop from the moment he gets up until the second he goes to bed and it has come to the point where my mum cant even cope with him because of his behaviour , I really am at breaking point and dont know where to go from here as i cant even go anywhere with him as im to ashamed of his behaviour [hsad]
I feel like a really rubbish parent even though i have always tried my best and never given him his own way with anything , knows how to share and has always been on a good diet (prefers carrots over chocolate) , I feel like a complete failure .

How do i go about speaking to a doctor about him etc ....

My son F has just turned 4 and I have been aware of some 'issues' for about a year or so and still struggling to get some firm diagnosis, mostly due to his age.

His elder brother O is nearly 6 and is on the Autistic Spectrum. His diagnosis only came at 4.5 years and was no surprise to me, having researched his symptoms and knowing him like only his mother could. Sadly the mother's input is usually an afterthought!

Anyway, back to F who has always been lively, albeit a bit clumsy and like his brother has delayed speech, often mimicing what he hears. Over the past few months, this behaviour has developed into grinding his teeth, constantly fidgeting, poking, pinching, biting and slapping - none of this meant unkindly but he seems unable to control himself. I am at the end of my energy levels and am struggling with knowing how best to help him.

I have, however, been down this road before, with O and have put the same assessments in place. He has seen a Developmental Paediatrician; audiologist; occupational therapist and Speech Therapist. I am now about to re-visit the first as, although it has been agreed he has some sensory needs, this is yet to be clearly defined. They all want more time to see how he develops, but in the meantime, we're left in the dark.

Ignore people who say 'do not rush to label your child'.... I believe these labels are good and can tell those around them to 'handle with care'.

He doesn't pick fights at school just at home or around familiar children such as family, thanks for your advice