I listened to some fabulous speakers at Invisible Fest this week, which was organised by Maddy Alexander-Grout. One of the things Suzanne Shaw talked about in her presentation was dividing her day into 3 x 8s - having 8 hours of sleep, 8 hours of family time and 8 hours of work. 
I know, I know, I can hear teachers around the world screaming "but that's impossible!" I totally understand where you're coming from, but you need to protect that family time as much as possible, otherwise you will reach a point where you become ill - physically and mentally. Working so many hours a week is not healthy and you shouldn't have to do it. Decide how many hours of YOUR time you want to give to work. Do not compromise your happiness and enjoyment and do not ever feel guilty about putting yourself first. 
The endless to do lists will always be there, learn to prioritise what needs to be done and be happy to leave things for another day. Don't be so busy working that you forget to live! Protect your time at all costs.