This is a hard pill to swallow. I can't really relate to this, since I am probably too young. But I am thankful for evey story like yours, OP. It reminds me to always wrap it up and staying away from booze. I don't know what I would do in your situation, but I think, that you need to get council by a lawyer, get the child support straight and after that, see the child as often as you can. You made a huge mistake with this girl, but now it is to late for regret. As a man you need to embrace the causes of your actions and act upon them. Distance yourself from her bullshit, don't even argue with her, because is pointless to argue logically with a woman. (I am only in my early 20s and have already noticed that.) Try to maximize your influence on the child and ones he turns 18, teach him about the way a man should behave. Stay strong and don't relinquish.
Edit: Maybe I overread it, but how old are you?
Edit: Maybe I overread it, but how old are you?