Started a side hustle to save for kids' college and it's killing me

I do freelance writing on evenings/weekends trying to build a college fund for my 8yo and 5yo. Sounded good in theory—make extra cash, stay sharp, build something for their future. Reality: I'm exhausted, I snap at my kids more, and my wife is basically solo parenting from 8-10pm every night when I'm working.

Last night my son asked why daddy is always typing and I had no good answer. Canceled my contracts yesterday. The college fund isn't worth my actually being present for them now. If I'm gonna work extra it needs to have built-in family time or I'm out.