The boy needs to get out and make the fun with others his own age. It isn't up to the mother to provide this. He didn't choose you to serve that function. The tie between a single mom and son is intense and the guilt or regret you feel is misplaced in my opinion though real and substantial. There needs to be a cutting that isn't a severance as much as a lifeline to his own needs and kind so you can have what you need. Could you really live a life without him? I think not. There is a middle place not found yet either due to internal forces or the nature of his age.