Think of sweet little bedbugs helping you clean, instead of brownies
When I get so down I notice the mess more than usual and have trouble mobilizing, I try to make it fun/funny. I put my "rutabaga" (love that word, it's so ridiculous!) plan into effect which says that if I'm that down and that unmotivated, I might as well do the worst things since they can't affect my mood any more negatively than it already is. So I start cleaning bathrooms or something I hate to do and a strange thing happens; I start getting all sorts of ideas of other things I could be/would rather be doing, LOL.