how to get my so back after he was taken right after i had him, right alone with my rights

Okay I was 20 years old I had just got out of college and I had and bestfriend who was my. To make alone story short I got her uncles kick me out of there home and I know clue were I was going to leave and I did not know anything about Oklahoma City at the time. I did not have anything but the cloths in the pillow case. I walking down the street and a guy pick me up and put me in and motel. I started doing drugs and everything I can to survive. Well I got pregant , but I DID NOT KNOW I WAS PREGANT until I went jail for some tickets and they took and pregance test on me. I had found out I was 5 mouths by then and I had already doing drugs when I got out I instancly stop and start getting clean but it was too late about a month later I was giving birth to my beauty son who I love more than anything. As soon as I had my baby a lady came in and said that I had coacaine in ,y system a little and he had none in his and that they were taking my baby. So after that i got discharge and they said I abandon my son. My right hand to GOd I never abandon my son. When she told me that my world stop. Now my stepmom got my son and he don't even know I am his mother and she don't even tell him that I am his mother like she said before she got him everything she told me she would do was a lie. I just want to try and get my baby back. I am married to and police officer now and I am drug free with children he is my only child. he don't mind her and all and he can't read as good and she is not even teaching him. I just to be in his permently. I'll try anyt6hing to get him back