Highly sensative person, Sensory Integration Dysfunction????I dont know

Hi to all, any imput will be most appreciated.... I am trying to diagnose my son Josh, he has had a hard time since birth really.  He is a twin to his sister Ally.  I went into preterm labour and delivered the twins at 31 weeks, my son was ventolated for only 7 hours and stayed in hospital for 10 weeks, he came home with an apnea monitor.  He seemed fine but as he grew older we had him assesed and he has had treaments from OT's PT's speech therapists etc, I thought that he was just stubborn as he grew into a toddler.  He seemed to be difficult with his older sister if she touched him or came too close to him... he however is nor sensative to human touch he in fact likes to be stroked and rubbed hard on his back or to be squeezed tightly.  He hates most clothes, labels, buttons, sock seams, long sleeve t-shirts with cuffs or sweat pants with cuffs.  he is most happy in loose fitting PJ's, and no schoes.  He used to be a bit of a toe walker... he is no longer.  He has been diagnosed with everyting from mild CP to idiopathic toe walker.  He is sensative to sound, but not if its loud, that doesnt bother him.  But a train in the distance no one else can hear he can, a dripping tap etc.... he is a perfectionist and wants the bath mat straight when he gets out the shower.  he wont dry himself and if his bed covers arent straight he wakes me up in the middle of the night to fix it.  He wont give in easy and hates new clothes and especially shoes.  He is sensative to smells....  He is also very loving and tender, he has very low pain tollerance.  I find him to be clever, he is very good at patterning and this showed up as very high on his cognitive testing, his speech is below average and he makes up words if he doesnt know the word.   He is very tall for his age and talks alot and is social.  If I ask him to do something (like homework) this way as he is not doing it right he becomes very despondent.  He has many hissy fits and throws things or hides shoes and clothes.  He hates his seatbelt.  I used think he was just being bad but little by little I am understanding him more, even so I find my patience is limited and we are always late for school and this makes his siblings mad at him and I get upset and somedays I feel like I cant cope and are not a good Mom.  Please anyone help me diagnose as I feel I am not ready to offer medication as adivse by the doctor just yet.