Try to remember that just like you, your son has to work through this major life transition. And I found with my kids, it took them a lot longer to adjust to the new way of life than me. Probably because I had been working and planning for it and to them it just happened.
Try to find some time to have a good long heart to heart with him and see if you can figure out what he really wants--not what his father wants. Then work towards that.
The most important thing you can do for him is not quitting your job. It's letting him know that whatever he's feeling, it's okay. And his feelings are important. It may or may not be possible for him to have life and school the way he wants it, but if he knows you are doing your best and you want what's best for him, it will all work out just as it's supposed to.
L