Want to fight for him..

I believe 100% that I was manipulated into giving my son up by my mother, and that my agency used me. I want to fight for my son, and bring him home with me like every baby should go home with their natural family if they can.. He has been with his adoptive parents for a little less then two months now, and I have already signed my entrustment paperwork.. but I have reason to believe that when and how I signed was in fact illegal in my state... But I don't understand, why is it so controversial that a NATURAL mother would want to raise her NATURAL child? The adoptive parents have had him for two months.. I had him for nine! But everyone thinks I'M heartless and I'M selfish for wanting to be a mother to my son! I have the utmost respect for the adoptive parents, but my son never really NEEDED them. And if they're meant to be parents, they will be, right? It seems like everyone cares about them before me, the woman who carried him and gave him life in the first place.. his flesh and blood, his REAL mother. People talk about disrupted adoptions, and most can only put down the natural mom. "How could she take that baby from those people like that?!" It seems the world has no respect for a natural mother.. especially one who wants to take responsibility for her child. That only makes her LESS responsible to society. To me, this is simply wrong... But what I would like to know is if anyone has actually fought to get their baby back after they've relinquished their rights and WON? And what are my chances of bringing my son home?