Sokmonsta,
DD (7.5) has aspergers/adhd, and I can so empathise with you on the release of tensions once in the safety and security of home and you and DH. Loads of people, including close family, never saw what we saw. Because she was good at staying reasonably in control "in public" and letting it all out when safely home with us.
It took years for us to get anywhere (from noticing, through asking for help, to finally getting seen and through that process) - we got her Dx 18 months ago now having first started to ask ourselves about DD when she was about 2. It probably didn't help in our case that she is an only child, the first grandchild in both our families, we are living 160 miles from both sets of parents, and I am the first WOHM in the family - so it was all different to what everyone else knew and lots of things were out down to us "being first time parents" and "both out working and DD in creche", even when we were questioning it ourselves (and creche were supportive of us too, although DD is high functioning so it wasn't clear to us or them that it was SN going beyond "normal" (perhaps somewhat difficult) toddler behaviour until near school age).
It means we can read up and talk to other parents about exactly how DD is "wired" and how to do things so she will understand, get disciplined, learn, respond to us, and enjoy life - rather than just doing things the way everyone else does them and failing (because she doesn't understand consequences, or is too hyper to hear what we are telling her, for example). And a side effect is that, although we asked to find out how she worked so we could work WITH her rather than against her, it means she has a "label" so while others may not understand the label, they understand that she is different and will make some allowances for it. (And we also get help from school not just in dealing with daily routines etc, but resource time which is working on a social and emotional education programme).
I am the diary keeper, the arranger of appointments, the person doing the courses, etc. DH is very much on board, but has had to accept a project based far-off abroad 50% of his time (2 weeks away, 2 weeks here cycle) due to the recession (and works when here too in local office). He can be much better at spotting and remembering triggers.
But we try to make sure that, if we have trips planned, they are talked about beforehand so she knows what to expect. There is time beforehand to let out stresses, and downtime/quiet time afterwards to release anything built up. We got a small trampoline for our small back garden - where she can just bounce it off. She will retreat into the sitting room and curl up under a soft blanket in the cool and dim to unwind. She will drink rescue remedy (there are kids versions too) in water to help. We rub her back if she will accept touches, or her head, or give strong hugs (she doesn't like gentle touches for sensory reasons, but strong hugs help her feel more grounded, we think). We take her DS lite for her to use if she needs to retreat from things but still be physically there (like coffee shops with us when she's bored, or big family gatherings she can sit in a corner or go to a bedroom with a cousin to play together), she uses her iPod and earphones to enjoy music but also to block out too much external noise at times. I always have colouring sheets, and now sudoku and other puzzle sheets, in my handbag with colouring pencils, to distract her. And a stress ball to squeeze. She occasionally uses ear plugs if it is very noisy (she can now explain that some things are too noisy for her). We will have a "backup plan" for outings, in case we see things starting to wind her up so that we don't get as far as meltdown stages.
It has taken a lot of watching and learning to get this far. And we are not entirely managing yet (back to school brings an increase in stress levels for everyone every year still - I was raging by text to DH this morning after a dreadful night and morning with DD, as he is away this week and school starts tomorrow, when he had been supposed to be here this year for it (school is open 2 days earlier than we expected, but we had known that before he booked flights - after we had done the planning for the next 4 months, but before he actually booked it) - and as I am on antibiotics so can't even have a stiff G&T once she's in bed nor share that load or get a hug myself, he really got a venting stream of texts so actually rang from SA mid-morning).
But it is still a lot better than a couple of years ago. And it does sound like you are starting to see the trigger points, and manage things to reduce DS's stress and anxiety levels - which is a huge positive. And the fact that others don't see what you do, is definitely a positive (even if it doesn't feel that way now) as it shows that your DS is totally confident in you and feels supported enough to let it all out when he bottles it all (or nearly all) up everywhere else. Keep notes for the Paed etc, and it's good that the GP is listening now (I did find that she somewhat fobbed me off as well - but I brought DH with me the visit that we were going to ask very specifically for help, as well as having the backup that the creche had actually suggested assessment to us too at that stage). And it sounds like school seem to be understanding as well, which also helps - even if it's only implementing strategies, that is a huge positive - the words of a dx help, but putting in place strategies to help any individual DC cope with situations is the biggest thing.
Sorry, that wasn't meant to be so long. I hope you get the apts soon and that those who are supportive, keep on being that way.