You've had great advice already 
You are probably still coming to terms with what your son does and doesn't understand. Take your time with that and learn to know his differences so you can help explain things to him when he misunderstands. Use very simple language, no hints, no body language, no meaningful looks.
Start from the point of view that he knows absolutely nothing about social interaction and take it from there. Watch your own language carefully when you interact with him, do you speak without inference?
e.g. "Your room needs cleaning" said to an NT child would elicit the thought oh dear I'd better get on and do that.
"Your room needs cleaning" said to someone with social communication difficulties who doesn't comprehend any type of inference is understood as just a flat statement like 'the sun is shining' or 'grass is green'
Don't punish him for things like that, he can't help it. He really does not understand.
Definitely pursue a diagnosis by a team of professionals usually Paed, SLT, Ed Psych and OT.
Diagnostic process is outlined here. www.autism.org.uk/about/diagnosis/children.aspx
NHS waitlist depends on your location, 18 months to 2 years from referral is common.
He may only have social communication disorder or he may have other diagnoses too. What is vitally important is to have him assessed by a multi-disciplinary team so they can identify his needs, clearly explain them to you and give you and school a list of strategies to use to help him navigate the world and his place in it.
Bear in mind that things which you've thought were just his idiosyncrasies could well be pointers to a specific condition, so get your thinking cap on and make a list of how he is different to his peers across the board. This info will help at his assessments.
What is he like at following instructions?
Is he immature? Many kids with AN are emotionally about two thirds of their chronological age.
Does he have any sensory issues? www.falkirk.gov.uk/services/social-care/disabilities/docs/young-people/Making%20Sense%20of%20Sensory%20Behaviour.pdf?
What is his co-ordination like? Does he do well at team sports like footy or is he better at individual attainment like swimming or horse-riding?
How does he manage to organise himself for his time at school, right books for right lessons, finding the right classroom etc.
How is he at home, can he plan and arrange a task you give him or is he all at sea and doesn't know where to start?
Success stories would be great!
The boy that you are seeing struggling now will change a lot as he grows up. The more his needs are identified now and the more interventions and coping strategies he's given now - mostly by you - so he can learn how to understand other peoples' behaviour will determine how his future pans out. You're already on the ball and willing to help, so his future has a good start!
Read as much as you can about autism and social communication, find what works for him. I used TV soaps for social communication "lessons" with dd as she was interested in them to start with. Does your son have a favourite TV programme or is he into Harry Potter or Star Wars or anything with a story where you can watch a bit of it together and get him to explain why the characters are behaving as they are as he perceives it, then you can explain anything he's missed like the nuances, tone of voice, simple body language etc.
Do monitor his social media constantly because if he interprets things literally there could be vast misunderstandings. Guide him carefully, it's a minefield for teens anyway, it can be doubly so for the ones who have communication difficulties.