ooops - I really feel for you.
Your ds sounds very similar in a lot of ways to mine. Chilled until he turned 3.
My ds is 4. He's been referred to an Educational Psychologist through his nursery. But there won't be a diagnosis of anything - he's far too young for that and actually may never need it.
But we are getting support, suggestions, strategies and understanding.
He has a few sensory issues that we've noticed, but nothing that prevents him doing anything normal. Only his teachers pick up on it and us - no one else has ever mentioned anything IYSWIM.
Ds likes the TV - he keeps still when it's on.
At nursery he has a squashy rubbery cushion which helps him to find his place in space without fidgeting too much. Letting him let off steam is vital. WE got a trampoline for that reason! aLthough it's fun too. wE make him bounce if he's off the wall for any reason, but make it into a game.
Being really really really clear with simple instructions helps as well. DS does not respond when I am sarky or vague or shouty. But he will listen if I get right next to him and tell him what I want him to do - no choices unless they're my choices.
ie "put your shoes on, then you can choose a car to take with you"
'Because I am your mummy and I'm telling you to actually works occasionally too! ALthough I told myself I would never day that!
He also has visual reminders of what's happening next so there is no arguing or wheedling or moaning (not saying he doesn't wheedle,argue or moan, but it's about reducing his ammunition ).
When I lose it with ds and shout he gets nervous and anxious. Until recently we had a bad spell with using the toilet - he refused to go unless he wanted to - and he started biting his nails to the skin.
We eventually put 2 and 2 together and eased off and the nail biting has stopped. As has the toilet troubles (for now ).
A lot of our stuff with ds is just immaturity. He will and is growing out of loads of the stuff which screamed 'ASPERGERS' or 'ADHD" to me. Other stuff lingers. Maybe he does have a condition.
But for now I'm learning to work with him and around him. SOme things I'll let him off with - eg he flaps his hands (big autism alert!) when he sees some things moving. I used to tell him to stop, but one day he told me he liked doing it when he saw things move in a certain way and I figured I should pick my battles.
RE clothes and shoes. I've been consciously buying more "comfy" clothes for ds. Lots of elasticated waist bands, soft tracksuity type fabrics, and tumbling things to make them softer. He comments now if something's really comfy and loves putting things like his baggiest trousers on.
Dh just came in and asked what I was so busy typing and I said "oh someone on MN has a wee boy who sounds a bit like ds"
His reply?
"Lucky them"