Dear White Rabbit,

You have to set your own boundries, sometimes it's just not possible to make two parties happy. I have the same thing here, I work, study and have a daughter. So yes sometimes I have to set my priorities straight and do what I have to do to keep me/others happy. And if that means I cant's serve my Dom in that period of time, so be it. Key here again is communication. Your Domme is worried that you work too much and you will burn yourself, but if you have experienced that you won't - and - it works for you this way, tell her. Reassure her that you will be back on your subbie knees when this is all over.
Sometimes Life doesn't give the opportunity to be in a D/s all the time, remember you are only human and society expects certain things which doesn't always match up with your lifestyle (kink).