My 18 month old has been diagnosed as autistic

My 18 month baby has just been diagnosed as high functioning autistic. My younger brother is autistic but never was diagnosed until he was almost grown because of lack of understanding the wide ranges of it at the time. My mother always blamed the shot but I was a bit skeptical but not enough to get his vaccines done. So he had no vaccines at all.
During my preg. with him I ate mostly organic as I could.(hard to find organic in my area) I know my diet was not perfect but not a SAD diet. So now at 18 months he is not speaking, just jabbering, rocking back and forth, stares at his hands allot etc.. but he is very social, maintains eye contact, smiles, laughs allot. However, I still blame myself but know that WONT cure him but what will? I know there is some diet link to helping them but my mom raised us to hardly ever eat junk food, no sugar, preservatives etc.. so we never had them much so I never developed taste for them. My boy only eats homemade food I make so at this point I am at a loss as far as diet. I do give him milk because he is only 21-22 pounds and the docs are saying he's underweight. At this point I am ready to cut out milk anyways but other than that he is not getting any "bad" foods. I think the causes of autistic are more varied than people think. Any thoughts to a grieving mom? Tweet