Jonzy, man slow down and breathe. It will be okay one way or the other. Tink has been giving you great advice, listen she is making sense. You have to quit assuming things and trying to read her mind. You like most of us men are fixers it's in our nature, but you can't fix it this has been the hardest thing for me also to learn it's a rollercoaster. With a WAS you believe almost nothing they say and 50% of their actions, as we all know actions speak louder than words.
Like Tink said go dark if it will help you detach and get yourself into a better space right now as most WAS do she is baiting you and you are biting. Quit being so available this was a hard one for me also cause again we are fixers. IMO you are still persuing her by asking her if this is still what she wants.
How do you act? "act as if", let this stuff roll of your ducks back. I'm not trying to be a jerk as I am still learning also but you are at a point to watch and wait. Detach detach if she goes to a lawyer there is nothing you can do about it, if she files there is nothing you can do about that either except validate her and listen, say something like I understand you want a divorce, though it's not what I want I won't stop you and leave it at that just cause she wants it doesn't mean you have to help her, walk away from it if you will let the conversation go at that.
If she has spoken to a lawyer, there is nothing wrong with you getting legal advice also, you have to cover yourself in this not too be mean to her but just to know where you stand, with things and what is expected of you for your son. Agree to nothing that you feel compromises yourself or your son ask a lawyer please get this knowledge.
Keep working on yourself and making the changes for you to become the man/person that you want to be, take each day as it comes get out and do things take care of your son. She has to do this on her own it's tough bro we are all learning, read the books they help set goals for yourself find an inner peace.
Don't take what I have said as being a jerk, I did not mean it to be that way, read other post learn from the wiser people on these boards and then apply what you can to your sitch and and continue with what changes you need to make.
