Can i just say I think you are doing great to have gotten so far!
I have a 3 year old and a bub same age as you and have been struggling with bf as well and think we are dealing with some reflux and really bad wind issues. The past week or so he's been chucking loads and at night time he's full of gas and is awake every 20 mins from 2 am onwards. We are all sleep deprived and emotional.
I'm pretty sure that formula wont help though so on with the bf. i stopped drinking milk yesterday and started him on losec. Last night he was much more settled, still woke 2 hourly for feeds but not every 20 mins.
I hope you get some relief soon for yours and your bubs sake, and know that you are not alone!