How can i tell if this is depression?

I am getting divorced, i feel better and less stressed with out him, however despite the fact that i never want to show my kids any type of sadnes, and on the contrary, i do laugh and play with them and i sing all the time, i also work a lot different schedules, (i am a banquet server) and in different places, i check the kids home work, on daily basis, make sure they go to school always keep them clean and well fed. there is a part in my life that im trying to fix, and is the mess in my house, for some reason i can't get to do the things that are absolutely necessary to keep my house the way i would like it to be. Every time i try to get to it, i rather go to sleep or just lay down, i don't find the enthusiasm to do anything, and it became overwelmingly messy. I tell my self that i am missusing my childrens time because sometimes im home while they are in school, but is not energy what i lack of otherwise i would not be able to work, and my work requires a lot of energy, but is enthusiasm.. how can i help myself, i need to fix my house, i want to make it nice for my children.. Please help.!!!