This is the main stigma of depression. From the outside people think you have no reason to be depressed, therefore you cant be depressed.
Completely and utterly wrong. Depression is often just an unexplained shift in your body's chemical balance.. just like an allergic reaction, or a cramp.. it happens with warning and without reason. It can creep up on you, or it can hit you like a ton of bricks.
There doesnt have to be any underlying cause.
Things can end up getting overwhelming, and you need to talk, to someone who you know will listen, and may come up with good ideas that can help you.
It ends up being a vicious circle.. the house is a tip, that gets you down, you are down so you dont feel like doing anything... and you know that you would feel so much better if you could wave a magic wand and have a clear tidy house and a clean slate so to speak. I get that feeling quite a lot...
My solution to the house.
Pick a room, any room! Get some bin liners, some cardboard boxes, and some cleaning wipes. Get some lively music on in the background... turn the PC off and the TV off. Box up things you dont want to throw away, throw away anything you dont need. Wipe down all the surfaces, hoover or sweep the floor.
Have a sit down.
Pick the next room...
You are not a failure, and it isnt your fault. Depression and lack of motivation are linked and not uncommon, but you can and will get out of it. :)