S.C.
We encountered the same situation when my son was also 2 1/2. We took the diagnosis because we also realized that he needed more services than what he was currently getting. At the time the only services he was receiving was OT in our house. After the PDD diagnosis he started receiving Speech and ABA therapy. Both made a world of difference! It was tought taking the diagnosis without being completly convinced that it was correct. My best sugestion would be to have your son evaluated by a pediatric neurologist. Truly they are the only one's who can make a true diagnosis. My son is now 7 and more developmentally delayed than Autisitic - but those early extra therapies were a Godsend, because regardless of what he was dianosed with - he needed the extra help.