observe his behavior. does he play with other children? does he tend to stare off into space? does he have uncontrollable tantrums? when he plays with toys, does he line them up in a straight row? is he sensitive to people touching him? does he have a oral fixation?( always putting things in his mouth, or always having to chew on something.) are there any delays in meeting his milestones? my daughter started showing signs of autism at about 1 1/2. she didnt get properly diagnosed untill the age of 4 1/2. of course see your doctor, but also look at all those things too. alot of kids are being misdiagnosed because they have 1 or 2 symptoms of something. always ask alot of questions, and do some research. good luck to you and your son.
get to a dr it sounds like he could have it... dont ignore the symptoms get them treated! ignoring them will not help him