Being a Birth Mother

I am a birth mother. If you don't know what that means let me explain. I had a child before I was married and had to give him up for adoption. He is my first born son and it was the hardest thing I have ever done. This was in 1972, in a very small town in the midwest and I was 19 years old, this pretty much has defined my life. I wish I could go back and do things differently. For about 20 years I had pushed this trauma in the back of my brain and tried not to think about it. One day at church there was a young lady, pregnant and not married. I don't even remember her name. I said to myself "I was there once." Then I had doubts because I had tried so hard to forget that part of my life not because it was so horrible but because it was painful to think that I had to give up a part of myself, my first born son. I spoke with an older lady in the church and told her about me (I didn't dare tell anyone for fear of being judge). She was really quite sweet and encouraged me to counsel women when they were in this position. Of course nowadays it is not shamed or frowned upon to be pregnant or to give up a child for adoption. It is open and talked about.
When people ask me how many children I have do I say 2 or 3? If I say 2 then I feel like a liar, if I say 3 I am lying also because he isn't mine, he belongs to someone else. But I gave birth to him. How do you not claim someone like that?
I have had contact with him and he does not seem to care for me. I have made mistakes in our "reunion" and I am not sure he has forgiven me. He just seems so angry. I wish there were some magical word that I could say that he would think I was interesting or that we had something in common. I would like him in my life. I am not sure what category that would fit in. I cannot mother him, nor does he need that. I guess all I would like is to be friends, to actually be acknowledged that I did exist. I email him and respond to his postings on this blog but he does not respond to me at all. That is so frustrating and maddening. Something would be better than nothing. Sometimes I think about giving up and just going away but I don't believe I should do that. I want him to know that I will always be here no matter what.
As birthmothers we get crumbs from our birthchildren. Whatever little bit of anything they will give us we cobble up and rejoice for days or months. It is pitiful. I am thankful for the sons I raised. If it weren't for them I would probably be consumed by this birthson.
So, here I am wishing and hoping and wondering what to do with this situation. Shall I give up or go away, shall I keep subjecting myself to his anger, to his ignoring me. I don't deserve this treatment. I wouldn't allow my own sons to do this to me but yet I take his abuse and keep responding to him.