There is hope...
My son was diagnosed with a sensory modulatory disorder when he was about 7 years old. I was given an article on sensory integration problems - the first line of which was 'Some children are more difficult to love than other but those with a sensory integration disorder are can be the most difficult of all'. I cried when I read it because although I loved my son there were many times that I didn't like him very much at all. Over the years we tried many things - all of which had some degree of success. We tried brushing with fine brushes and this seemed to lessen the sensitivity to touch although it cost a lot in time effort and money.
I went on a parenting course which helped take the emotion out of my response to his behaviour - I would recommend this to everyone. We were advised to try him on an anti-oliogenic diet [this took years to get through but made the most difference of all. The diet was suggested and supervised by our local hospital. We saw a marked difference in 5 weeks although by that time my son had all but given up eating because he was so bored with the diet. 2 years later we had a good range of foods in his diet with a number of food types clearly identified as exacerbating his difficulties.
I worked with him to help him identify what the bad feelings were, where he felt them and to grade them according to how bad they felt. He was then able at quite a young age
to monitor his behaviour and remove himself from stressful situations before he lost it.
I now have a son, aged 18 years, who goes to work on his motorcycle and has a lovely girlfriend. He still has his moments but on the whole he leads a very normal life and is a pleasure to live with. My advice is not to give up, to love the child you have not the one you feel you should have had
and to try a variety of different approaches. Good luck.