Hey there,
I hardly ever post but from reading your post, if your son has Asperger's, my son has Asperger's, and I don't think my son has Asperger's.
Early reading, not so good on the socialisation, poor drawing (and how!), a tiny bit obsessive (in our case it was fans or things that went round).
If you should be panicking, I should be panicking too.
My son is now 9. He is still a bit of an introvert. And still an excellent reader :-)
The idea of a 'diagnosis' which I interpreted as an ASD was raised when he first went to school as he refused to participate in class. However they didn't realise that he was very far academically advanced of where they were pitching lessons, ie reading novels and being given picture books. When that was fixed (new school and grade skip) the social and participation problems diminished.
Best of luck, my uninformed opinion is, don't panic. I hope these responses make you feel a bit better about the situation.