If your only bringing home 37% of your pay I wouldn't worry about keeping that job.I'd be looking into getting around this, otherwise your going to spend the next 13 yrs spinning your wheels in the mud.
Again, here where I live you don't have to be in the same school district, you only have to be able to get the child to the school he/she goes to, on time, every day. Maybe you could half the distance..... commute to work and drive your son to school the 2 or3 days hes with you.
Giving up a 52k professional job with a company I've worked for and accumulated 12 years of seniority doesn't strike me as a particularly bright move. There are no jobs (unless you count truck driving or Wal-Mart greeter) where my son is now.
As far as halving the distance, that leaves me 35 miles from his school. My attorney tells me I need to live with a 15 minute drive to do shared parenting. And, even with shared parenting, some money would still go to the ex because she earns less than me.