I am struggling to know how to proceed as I am worried that my DS has massive red flags for being on the spectrum somewhere. It runs quite heavily in the family, and my younger child had diagnosis of autism at 2.5. Her main issues that raised red flags were her speech and language delays and how she communicated. She is also very anxious about changes to her routine and always needs to know what is going on. She copes well with a visual timetable, uses PECS although she is pretty verbal. She is now 3.5 and attending nursery with a 1-1 support. She doesn't have massive sensory issues that are noticeable, although she doesn't like getting messy and noises sometimes upset her.
DS, on the other hand is a different kettle of fish. I have always felt that he was different. He was very bright, very early reader and quick academically. He lacks confidence physically (slow to crawl, walk, pedal a bike, etc), and as a toddler worried me with his extreme tantrums (would often try to bite or scratch because it was time to go home etc). However, he has always been very good at following rules and has always been mostly well behaved at nursery/school. He impresses people because he is very clever academically and comes aross as articulate. He had only one incident at nursery ever, and that was him having a wobbly at 3 because they wanted him to say sorry for something which had been an accident. He ended up trying to bite his key worker, who was trying to make him say sorry. He was 4. He continued having 'tantrums' after toddlerhood - seemed to get worse around times of change - Christmas, his birthday, etc. He has always been OK at school, even if he wasn't happy about something there. He is very 'rude' at times and very blunt. He is always enraged that he has to do what grown-ups say and they get to make all of the decisions. He complains that he never gets to choose anything. It's almost like he has no idea of authority.
He started year 1 this September and hasn't really been enjoying imself since. He does not like the work as far as he is saying. I believe this is because they give him things he finds very easy, but involves a lot of faffy cutting out or colouring in or similar which he then finds frustrating. He also appears to dislike the creative writing tasks the most. He has been told off by his teacher for not doing enough writing, but he says his attention is distracted away by the noise and the talking of those around him. He is waking up every morning with a stomach ache and saying he doesn't want to go to school. Some mornings it's a trial getting him to put on his pants.
He hates losing at anything. He still talks about when he came second at a game of lazer quest 2 months ago. He did very well, but he actually cries about it at night. If he loses at anything he is extremely upset. And remembers it for weeks/months. He has always been this way.
He has real problems with smells and a very active gag reflex. He gets truly hysterical at certain sounds and in particular cannot cope with his hands being wrinkly after swimming or the bath - almost always result in a wobbly.
He gets extremely distressed and shouty and starts 'tantrumming' very suddenly when things don't go his way. On Friday he wanted to go to the park after school. His sister was very distressed in her pushchair and we needed to go home for other various reasons (shopping delivery). He was full of hell as soon as I said no, despite his sister rying loudly in the pushchair and me explaining my reasons. We got home and he caused a massive scene out the front, refusing to come in. "I NEED to go to the park! You don't understand! I NEED it!" Eventually he came in and was screaming and yelling at us. DD was getting upset by his shouting and I suggested as calmly as i could that he go upstairs to calm down for a while. He refused - several times. We have prearranged (with his agreement, while he was calm) that he should go to his room as a safe place to calm down. The next step in the agreement is that I count and he needs to be upstairs ASAP or face losing his iPad use for the whole day. He still refused. He finally caved when I reached the next sanction. He then went upstairs and slammed his door lots and had a huge screaming fit 
. Later, when he comes back downstairs, he almost cannot remember what he did or why.
This is typical of what he does almost every day for one reason or another. It seems to be getting worse, not better as he gets older.I really want to help him. His school see none of this usually as he complies almost always in school, but then brings his stress over school home and lets it out there. He seems to have problems socially - he stands out like a sore thumb as he doesn't seem to be on the other kids' wavelengths at all. I have walked past the school and seen kids who are supposed to be his friends being quite mean to him. He mostly just takes it and doesn't seem to know what to do. He wouldn't tell a teacher to get them in trouble, and he never really complains about this. He always says it's the work that bothers him about school - he says he already knows it and he doesn't like always having to do it. Obviously he has to go to school, obviously he doesn't already know everything, and I try to explain this. He is very capable and picks up new concepts very quickly.
So what do I do? If I speak to my GP, what is likely to happen, if anything? I would hate to see him labelled, but if it is getting worse I think we all need a bit of help. I am very worried about him actually. My DD is the one who on the surface has the biggest struggles but actually I worry about him so much more as he always seems unhappy nowadays.
Sorry its such a long OP. I am grateful to anyone who gets this far.